Righto, something I guess I owe Anomander for quite some time:
mecha engineer overview:-The mecha prototype progression seems to have some typos with "The grade level and Arsenal options available increase to 2 at a class level of 4; to 2 at level 7; 3 at level 10, 4 at level 13; 5 at level 16 and " ending right there. So increases from grade 2 to grade 2 between 4 and 7 and nothing after 16?
-Prototypes be real cheap. Like, you can get the lower ones for cheaper than a suit of fullplate. What raw materials are you using that 100 gp will allow you to build a 30 feet tall mecha? And seems like you can get them moving on their own since they have their own stats, and there doesn't seem to be any control cap. That's some of the cheapest minionmancy I ever saw to be honest.
-So puny creatures can pilot your foam mechas, but the super talented pilot cannot? Unless they're your slave then it's ok. Honestly that just feels tacked. If anything I would suggest for replacing it with your foam mechas caping the limits of the pilot. Like you may be a super pilot with 20 Bab and 18s on all stats, but the foam mecha just has too much lag so they'll count as 1 Bab and 12 on all stats.
-It's understandable why there seems to be a love for "real" prototypes. Because the "lose when hit by critical" becomes meaningless if you don't get hit at all, so load up on AC acessories and you'll be easily pulling ahead of any real pilot. Trying to make a tanky prototype in the other hand would be a waste of resources so I guess that's why super pilot still gets played when mecha engineer is available.
-You can use prototype's Bab whitout losing anything, so low level parties are better off ditching their machines and buying from a lv.20 mecha engineer.
-Mecha Engineers also get the best cohorts because only they can take mecha engineers as cohorts. Sure, win more. In the other hand no exception for followers, and even a low level mecha engineer is pretty brutal.
-Any two disciplines of your choice choice. Besides top leaders and merchants, mecha engineers are also the best martial artists among pilots. Sure stances cost hardpoints, but you already have more hardpoints than a full party of super pilots.
-Sapper has a constant DC of 25 since mecha do not have effective HD.
Also sure, high level mecha battles should be about just hacking open their cockpits in one round ignoring all the mecha's defenses and killing the squishy pilot inside. Kinda implied it only works on unattended mechas, should clarify about that.
-Just noticed now, but since a)you can take mecha engineers as followers and b) they always fit inside a mecha and can take actions then the only winning move is to cram your mecha with an orgy of mecha engineers.
-Hook lacks HP to be sundered (and then what, you lose it forever?)
-More hardpoints. More AC and assorted defensive abilities. Less crits taken.
-Joke's on you making Ablative Plates obsolete since Ablative Plates no longer are an arsenal option.
-That's some really video-gamey radar. I'm sure DMs will be delighted for being forced to declare where every enemy is looking at every round. Also pierces every disguise and any lie ever to find out who's an enemy or ally so mecha engineers now best diplomats, security agents and spies too.
-Even more hardpoints. I'm not sure if there's enough arsenal options to fill all of them but sure go ahead.
-Underclocking's penalty may mean something if you didn't have a legion of mecha engineers crammed inside that can patch all status conditions every turn too.
-Integrated Technology and Mecha specialist are yet more of those abilities where it's screaming for minion abuse or simply hiring NPCs to grant you the benefits forever.
A lot of the above problems could be easily prevented if you simply flat out declare all mecha engineers won't become cohorts/followers no matter what nor hire themselves for cheap one-time jobs or something, otherwise it's just screaming for mecha engineer 24/7 orgies inside mechas. Or something that each mecha can only be tampered by one mecha engineer at a time. Also why all the weird hardpoint formulas? Couldn't you just go "get one extra hardpoint stacking with previous extra hardpoints, move on"?
Sorry for any abrasiveness but again I just disliked the concept from start, although all in all seems like a
nice* dedicated job and if the above issues are taken care off and I would even add it to the main index. Now to see if I can catch some sleep.
*EDIT: Scratch that, I just did some deeper math and your class at 20 is getting some 17 whooping acessories with no need of touching their starting 30 arsenal. That's completely insane, and even more when they have several abilities that make the arsenal options obscene all around. Even assuming that you need to spend 6 in lower level stuff (and still plenty of strong stuff down there), that's still 11 tier VII arsenals.
The hardpoint spam madness need to go too. Hardpoints were designed assuming you only get an handful at best. There's no sane way to balance something getting triple that, even less when they're boosting the arsenals and you barely even started to scratch the class boosts.
EDIT EDIT-Your main feat also has some issues. The whole thing where you trade spirit points for arsenal space and pseudo-acessories makes the feat nothing short of an auto-take for every pilot and their mother because spirit points scale up with level while arsenal/hardpoints do not (except for the master race engineer, but that one gets the feat for free anyway).
