Action points in tactical battles need a good deal more explaining within the UI, I think. First of all, where do they come from? Other than common sense, there's nothing to tell you that action points and combat speed are related. Especially since having two different values (1.0 starting combat speed vs. 2.0 starting AP, but they increase on a 1 to 1 basis after that) can only be confusing. Given that they're basically the same thing, why not just combine the two stats entirely?
The change to making spells take 2 APs is a good one, but again it needs more explanation. For example, the wisdom stat in sovereign creation says that it changes the AP cost of spellcasting. Great. But by how much? What's the relationship? Secondly, the wisdom stat isn't displayed ever again anywhere in the UI at all, in spite of its continuing effects on the game. I picked up a random merchant NPC and imbued her, with the intent of making her my spellcasting firepower... only to discover that she couldn't actually cast spells, because her spells cost 2.5 AP, instead of the normal 2.0. I can only assume that she had a crappy wisdom stat, or something, but there would have been literally no way for me to know that had I not just happened to spot the wisdom tooltip on the one single occasion it was displayed.
There are a number of ways that you could solve this problem, the most simple of which is by just displaying the wisdom stat on the character sheet. But personally, I don't think the wisdom stat serves enough of a purpose to warrant its existence at all, and I don't believe that trying to increase its usefulness would add significant depth to the game. Why is it even there, given that its purpose has been entirely inconsistent over the course of the game's development? Is it just some bizarre D&D throwback, a relic of a bygone character system shoehorned into a combat system that it's struggling to find applicability for? Or is it just a desire to have the symmetry of three physical stats and three mental ones? I tend to suspect the former explanation, given that the stats are so conspicuously named identically to the D&D stats. Even if it's the latter, that still doesn't work, because combat speed, in many ways, functions as if it's a core stat. It's a force multiplier, like all of the other core stats. All of the others, except constitution, that is, which is merely an additive value. Yeah, combat speed is more of a core stat than constitution is. (I'm not suggesting that constitution be changed to a multiplier, obviously, since survivability is already boosted by defense, i.e. dexterity.)
The third thing I've noticed is somewhat related to the second one, and in fact I already mentioned it in passing. If you have inadequate APs to cast a spell, you literally can't cast a spell at all. The consequences of this are twofold. Firstly, it's a complete noobtrap. You can screw yourself over by imbuing an NPC who will still be incapable of casting, unless you expend several levels worth of combat speed increases which would normally be far more usefully spent on essence. And secondly, this is totally inconsistent with literally every single other expenditure of APs, or even movement points on the strategic map. Anywhere else in the game, if you have even the tiniest fraction of an action point or movement point, you can take actions that require said points. Consistency is key here (or in fact anywhere). Making it so that spells can still be cast if you have less than the required AP would both eliminate the noobtrap and make for a less confusing system overall.
My last point is kind of an odd one. Currently, combat speed "feels" like an inferior choice for spending level-up points. Which is odd, because in terms of cost-effectiveness, it's identical to strength. This is likely because it requires several levels worth of upgrades before you reach the magical next whole number, that allows you to actually take an extra action, and get any kind of benefit from the points you've been spending. Whereas points dropped into strength give you an immediate, useful, and above all noticeable boost to your attack power.
