I'm pretty happy with most the system, but I have a serious problem with the Accessory nerfs. As they now stand, accessories cost 25 arsenal, but grant both a buff and a nerf. Arsenal is a pool of what is supposed to be points making you stronger, but post nerf, you spend your upgrade pool on specializing and altering your mech in a way that could just as easily be handled in the manner of giving Real Pilots their Arsenal tier worth of slots to mess around with their mech.
Speaking of slots, I'd like to propose an alternate way to handle accessories that would hopefully allow you to return them to their proper power level without any issues with them being unbalanced. What I propose is to switch accessories to a hardpoint/slot system (much like in the games), and to remove the nerfs on them. Additional Parts slots would be purchased with Arsenal, or with Upgrade on Supers, with additional slots costing more to naturally limit the max number of parts slots -- for example, 25 Arsenal for the first slot, as per the existing system, but then 50 for the next slot, 75 for the next slot, and so on, with each additional part slot costing 25 more than the last in this example. This is already well modeled with Hyperdimensional Storage for Supers, which could just be directly converted over to buying parts slots, since that's both the best thing to do with that upgrade and the reason why it was a mandatory pre-nerf set of upgrades on most super robot builds.
The existing accessory nerf hits Supers hard, as it greatly decreases the value of Extradimensional Storage. For Supers wanting special weapons like armor breakers, there should still be a way to get Arsenal. Maybe provide 10 Arsenal for free and force multi-classing for more. Maybe still let it be bought with Upgrade. The above numbers are suggested due to their match with current values from Upgrade, but could well be different. They're primarily provided as examples to illustrate the point. This would also provide an extra advantage towards taking Reals with built-in free accessories.
I believe that the biggest balance problem here is that it's trivial and used to be highly rewarding to grab tons of accessories as a Real, as your inbuilt weapons generally provided most or all of the combat options you needed, and Arsenal weapons cost very little Arsenal -- a heavy weapon like the Burst Railgun is only 10 Arsenal. Contrast with the games, where it's 40 W-Gauge in OG1, and 30 in OG2. By the current system, this is necessary to make Arsenal normal weapons at all desirable, as they must directly compete with accessories; unless you had less than 25 Arsenal left, by the pre-nerf system your best move was always taking another Accessory.
If you want to use Arsenal for accessories, there's a few good solutions that immediately occur to me. You can nerf them, which you did and I dislikebecause it makes them stop being special. You can increase the cost of normal Arsenal weapons, so characters have things other than Accessories to spend their Arsenal on, except likely that just means players will ignore arsenal weapons almost entirely, which I assume goes against your design intent here. Of course, not using Arsenal for accessories at all and giving each Real on the list a Part slot count would also work, much like in the games, but by the way this hasn’t been done, I am guessing that for some reason you consider this undesirable to the design.
You know, I can't really remember why I didn't just do that from the start. And it allows for pretty much what I want, that you'll pick a bunch of acessories and weapons.
Acessories no longer give penalties and now demand Hardpoints. Supers/Reals/Ships/multiclass updated to have those. I left the old lists in place for posterity's sake and people who don't want to update their sheets again. Although the number of acessories/weapons you can take should be about the same.
-Hyperdimensional storage grants Hardpoints.
-Super Robots and Battleships gain 4 free Arsenal space.
The change of accessory from individually purchased to buying slots works poorly with the accessories with nonstandard costs, of which I think there are four categories: Refined Armament, Cartridge, sense-granting parts of cost 9, and such parts of cost 19. Solutions are varied for each. For Refined Armament, either move it to a different category to still be bought at 5 Arsenal, or make a single part slot filled with it apply its bonus to up to five weapons (or, since most units don't have more than five weapons anyway, just simplify things by making the one accessory apply to all weapons). Cartridge would be handled similarly: keep it Arsenal cost 2 instead of being an accessory, give pilots twelve of them to a slot, or buff them to the power seen in the games. For sensors, again possibly make them not take accessory slots, or allow three cost-9 sensors to a slot, or a cost-19 and a cost-9. By the current Arsenal numbers, those all should be of equivalent value.
-Made Refined Armament apply to all weapons and allowed it to be combined with one Radar option, which can be taken multiple times stacking
-Combined Ablative Plates with the anti-radar systems.
Another possible solution to the nonstandard cost issue is to do percentage-based or static increases in Arsenal cost for each additional accessory: the first is the listed cost, the second costs 5% more than the normal cost for the accessory or 2 arsenal more, the third costs 10% more than base cost for the accessory or 5 arsenal more, and so on.
As a side effect of this change, normal Arsenal weapon costs could be increased to price most of them out of range of Supers, which is good -- Supers aren't supposed to be using mook weapons, especially not awesome ones like the Shishioh Blade or the Graviton Cannon. If you disagree with this and consider that a desirable outcome the system, it can still be allowed under this system by allowing Parts Slots to be traded in for 25 Arsenal each, thus making powerful normal Arsenal weapons still obtainable for Supers, but requiring the trade-in of multiple Parts slots, thus only being worth doing on highly specific builds (like ranged super).
Well now Super Robots have 4 arsenal space that allows for some back-up firepower but none of the heavy hitters. If you want Dancounga-style, then that's for what Real/Super multiclass is for.
Thank you for considering all this. Good game design is important to me, and I think this mod is a great base overall. I'm happy to be a player in this setting, there just still a few things to work on in my opinion. For things where you disagree with me, I'd really appreciate hearing your design intent, and your reason for doing things differently. I'm currently working off the assumption that your goal is basically 'like Super Robot Wars, but d20 and with all the benefits of the SRD behind it'.
100% correct on figuring out my goal. Thanks a lot for that help! Your scaling costs ideas was interesting, but eventually I believe modules/hardpoints are both simpler and closer to the source.
Also, the combining robot system in Mecha Mook doesn't seem to have been updated for the EN overhaul
Combining Robot updated.
Hopefully I'll be able to give a more detailed answer later today or tommorrow.
Really, the tl;dr is everything form weapon damage to cost should have had a balancing formula to it. Like cost specific, if you did say 1pt ammo, 2pts sensors, 4pts basic equipment, 6pts refined, you could balance all your costs. Later in post, you can inflated it to a 50~300 point system since the numbers them selves are arbitrary. But if you decided something should cost 225pts it should equal to something like a [basic (4 or 200pts) + 1/2 ammo (0.5 or 25pts)] and if it's not then you know it's cost needs a different value.
Siflux reminded me correctly that in SRW games Arsenal weapons and acessories consume different separate resources, and all of the acessories have the same cost.
Eeerr, Arcane Pilot has plenty of Divinations, from the humble Detect Magic to Locate Object to Clairaudience/Clairvoyance to Locate Creature to True Seeing, several more all the way to Foresight.
The core problem is you started at the SRD list and then started cutting Spells out which ended up leaving a theme of patchwork (no scry until lv14?). Like you have Alarm sure, and all the other upgrades for personally sleeping safely at night but you can't Fabricate a series of walls to protect more than a half dozen people or Move Earth some trenches in for warfare. What you have is a mech sized magical plate that can hold dirt the caster's mech sized bare hands have to pick up using his mech sized shovel that deals minimal damage to dirt. 
Some of the cuts make sense for balance sake, but if you're looking to balance the List then it also needs to be balanced to what the other Classes can do. Like yeah maybe the Arcane Pilot gets the same bonus Feats Super/Real does, but so does the Real/Super and that's not going to change the fact the Real/Super have exclusive extras for attack countering. The Arcane (and divine) should also get their own alternatives too, specially if you feel players need it to begin with.
Arcane/Divine have spells and no maneuvers. Supers/Reals/Captains have maneuvers and no spells. And I'm pretty sure there's a lot of Immediate Action spells out there to pick if you want to go that way.
Why yes, the intention is for Arcane Pilots to specialize in a certain type of magic instead of every mage character knowing all of the uber spell ever without real effort. And any of the spells you mentioned are enough on their own to make the Arcane Pilot a MVP for the party.
>.>
You have a funny way of wanting Arcane Pilots to specialize in a limited report of Spells. For one thing they can't choose a Spell that supports their specialty until a level after they gain the new Spell Level and "Favorite Spell" always shows up a level before you can choose your actual favorite Spell so you always "favor" spells you hate using.
Eeerrr, you can change your Favored Spell at every Arcane Pilot level up.
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Then as you're doing in the game you can get extra spells through a variety of items.
Yeah but Phantasm Star is a high powered game, some List snatching is expected, and Super Robot Wars the Campaign setting is not forced Gestated & high powered. 
True, although I highly recommend the Gestalt bit, in particular so that Reals/Super pilots have something to do besides smashing face.
And really need to work on properly fleshing out that general fluff. Right now using this material is heavily dependant on the DM coming up with their own adventures/plot.
Actually been working bit by bit on creating a sample world based on our campaign so far, in particular how Parum developed and descended into total war, the different factions competing and how the Android Administration rose to power, while new technologies were researched and some planets of the system blowing up, but hard work is hard.
That being said you can set aside the differences in expected scale and look at the heart of it. Because I had to invest I wanted to increase the return, one thing led to another and in cause and effect Bahamut really doesn't have anything you'd call a cool item, since he's just a dragon on fire that spent most of his wealth trying to obtain Spells Arcane Pilot doesn't have.
Hadn't you said you didn't even spent most of Baha's money?
Anyway a bunch of knowledge boosters is still cooler than generic number boosters.
And that's ok in the build. The RPs been fun, next level I'm a lot less constrained with my buffs with got me to pick some more interesting ones which are still pretty new to me. But Bahamut & Phantasy Star aside, Arcane Pilot has some problems. Even the Warmage, Beguiler, and Dread Necromancer gets Splat Spells. If you want the Arcane Pilot to really narrow in on some favorites, less choice isn't the solution but more. Like you could cut the default list some more so it's purely basic role fulfilling then triple the open space giving them at least three Spells of every level to pick.
Not sure if you mean spell level or Arcane Pilot but three spells per either is a nope.jpg. The super/real get only 20/19 maneuvers and some stances from a much more limited list and that's it.
Now Warmage/Beguiller/Dread Necro do get splat spells. From the splats they were printed on. So I guess I may continue the Phantasy Star conversions and turn their techniques into generic Arcane/Divine pilot spells and the game skills into feats those two classes can take as bonus.
The basic plan would be that those spells are divided into 6 main groups (Fire, Ice, Lighting, Wind, Light, Darkness) and they can all be cast with different actions from Immediate to 1 round. The longer you spend casting a spell the stronger it is. Each "element" then gets some feats to boost it.
When people are limited they always grab what can give them the most. Like in another lovely SorO analogy. If you're poor you walk into Walk-Mart and throw a bunch of Hamburger in the cart because you can cook that in all kinds of ways and Hamburger Helper literately sells pasta ideas you can create after visiting the baking & spice section. But if you have the money to spend, you might instead walk in and think I want Tacos and BBQ New York strips which just doesn't have Hamburger in every option the guy with more restrictive limits has. You don't have to pick Polymorph's ominous solutions if you can pick up a number of unique Transmutations you like. You don't have to pick up Orb of Acid if you have the spare room to pick up different elemental Spells or even more than one area one Spell. Etc.
You'll always have a narrow section of people that will try to abuse the system much like the rich guy that refuses to pay his taxes, but choice breeds the ability to select things that do not amount to the best swiss army knife.
I'll still rather write my own custom spells and feats than dig through over a dozen splats. And if then a player really wants something from splat X, they can take it.
