That may be true, so I'm going to write out a bunch of background that I hope explains what I was trying to do. In writing the class, I was aiming for a niche that involves a lot of things - spellshaping, melee combat, and mounted combat. What I tried to do was hybridize all of those. In order to use your spellshaping to its greatest effect, you need to be in melee, and you need to be mounted. Your spellshaping makes use of your mount directly, and your class features are primarily geared toward streamlining mounted play (eliminating fiddly, little rolls) and ensuring a durable mount. In my experience, the biggest problem with most mounted combat classes is that you either have a mount that's irrelevant in combat, or you have one that's as good as another character in the party. By making it a fixture for your own abilities and making it difficult to destroy, I'd hoped to create a mount that would remain meaningful without feeling like having a new party member as a class feature.
The class began as an attempt at a "partial spellshaper". I tried a lot of different angles (you can see the original draft as the
Magitek Knight), but I just couldn't get it to work in a balanced way. The second tier One Soul as Two abilities were always intended to be the core of the class, but after a lot of back-and-forths with DonQuixote, it became clear that spellshaping as a system just isn't designed for a stunted progression. So, I decided that I had to move them to a later point and restrict the power of the formula you shape through them in some other way, which I decided would be by using a metashaping degree. You've correctly determined that Quicken was relevant here. I priced it that way because it's a very similar effect - getting a major formula without using your standard action. I have only just now, however, realized that the action requirements to trigger it are so steep as to merit a discount. I hadn't quite realized that you need to attack
and use a swift action to get it to work, so you don't actually have the option of dumping out multiple formulae in a round. Likely, as a first try, I'll decrease the cost to degree 2 and swap it and the first tier abilities. I'll need to think about it.
Anyway, all that said, I think the class actually has more mounted combat abilities than most mounted combat classes in 3.5. I don't know about Pathfinder, but everyone else pretty much gets a mount, and that's it. This class gets a mount at level 1 (pretty much unheard of, since a horse is already better than a level 1 character, which mandated all the new creatures), bonus feats that work in conjunction with mounted combat, a way to use your mount's actions to special effect, and three class features specifically dedicated to making your mount work better for you (Improved Mounted Combat, Cavalry Master, and Surefooted Charge). Aside from One Soul as Two, though, they're all pretty generic, I admit.
However, I do totally need to add an immunity clause to Spelltrigger, and add the bonus damage I'd meant to put in there (the ability was always a bit bland). You'd be adding your Intelligence modifier to damage with an attack shaped in that way, which is a nice edge but probably not enough to put it over the top compared to the control or combo options the other mounts allow. I also need to specify that Spellcurse deals its damage
after the action is taken, so that it doesn't do anything like interrupt spellcasting, which would make it far and away the most powerful.
It'll be a bit before I can actually make these changes to the class, and when I do, I'll probably add the mount-free ACF that borrows heavily from the Anchorite. But until then, you can consider the following to be errata:
You and your mount are immune to the negative effects of a formula shaped with the Spelltrigger ability.
Whenever your mount shapes a formula on your behalf through your Spelltrigger or Spellbeam abilities, add your Intelligence modifier to the damage dealt by that formula, if any.
Each 2nd tier One Soul as Two ability requires that the level of the formula you shape, plus the degree of any metashaping feats you apply to that formula, plus 2, be equal to or less than 1/2 your shaper level (rounded up).
Thank you for the post! It's pretty helpful.