So here's what I'm thinking would be a decent place for the kind of powers the different classes get to pull out:
Martials get 4 exertion per encounter. Their class provides them abilities that cost an exertion to augment what they were already doing with a weapon attack or whatever. So you swing on your turn and add a Rider on top of it that deals more damage, pushes enemies around, whatever. For 2 exertion, you can do the thing -harder-. Doing more damage, extra targets, further distances, etc. All based on the class feature.
Arcane gets 2 spell slots per encounter. Arcane Spells tend to be more effective than what a martial gets out of 1 exertion, but similar in power to what 2 exertion does. For a straight up spellcaster class there's a whole spell list with bigger and smaller spells (Daily vs Encounter) but for Arcane characters that aren't full casters, like a Swordmage gish-tank, the spells are class abilities like the martials get, but they still get to pull their daily spells off the big spell list they share with the rest of the Arcane.
Divine gets 2 spell slots and 1 channel divinity per encounter. Channel divinity is supportive regardless of your specific class, though whether it's healing or a buff or something is both class and/or subclass specific. Spells are a little less powerful than the Arcane ones, but always have some beneficial effect separate from straight throughput.
Nature gets 3 spell slots. All their spells that deal damage also add control effects. All their control stuff is just flatly better than anyone else's controls. Spells have a similar throughput to Divine casters. Whether you're in melee, blasting AoE, or skirmishing, you're doing your best to lock people down for funsies and effectiveness!
Occultists get 2 spell slots. Again, less straight throughput from Arcane, closer to Divine. But all of their abilities provide some kind of debuff to the target. That can be some control like knockback or drag, but penalties to damage, healing, movement, attack rolls, etc are all, also, part of the schtick. Also some Curses along the way because come on, curses are important!
Psychics get 2 Psi Dice. Psi dice don't always get expended when you use them. You apply them to your powers, powers get stronger, then you roll the dice to see if you keep it. You can apply up to two psi dice to your powers, but you always risk losing them. If you do, you have to wait to get them back. If you don't lose them, you get to keep using them.
