As another option, use a mechanic similar to spellcasting. Each PC has "combat points", similar to Favor or Power, equal to their relevant stat (or highest stat of ST/AG). Using an action costs a number of these points equal to the recharge of the action. These points have "equilibrium", and will replenish one point per round like Power/Favor. Since there is no "channel power" or "curry favor", powerful actions will naturally be resticted in how often they can be used. You could also allow a character to suffer fatigue for additional "combat points" on a one for one basis, for example, simulating a heroic/extra effort to perform an expensive action that the character doesn't currently have points for.
Personally, I think that I like the second option … but it is something else that needs to be tracked (in a sense) as it is another pool, so is still a little fiddly.
I like this too, and have considered something like it. But it still involves tracking points. And one would probably have to redo some more of the rules (for example on-going actions, and how delay result affects the pool). Also dual tracking for wizards/priests is a bit inelegant.