I can see wanting a particular facet (such as Powers) to be relatively consistant, the same way we'd want all saves to work approximately the same way - roll a die and add the applicable bonus.
I'm thinking that you could adjust the powers that call for a save without a check to make them checks instead of saves - make it a power check with a DC generated by a formula based on getting the same chance of success using the subject's applicable save bonus. For example, instead of the subject saving against a DC of 10 + 1/2 Adept level + Ability (or however that formula is setup, i can't remember), it could be a Power check DC of 10 + twice the subject's Save bonus, or something to that effect. Someone more math-oriented than I can probably tweak the formula to make the odds match up better, but I imagine that exactness is not the issue, just getting approximately the right odds in a simpler or more consistant way.
On the other hand, if the problem is just for your player trying to remember what to do with different powers, you might try my method, wherein each power lists a brief, simple code. c=check, s=save, l= level-based, and -=innate (like talking with animals). Some powers will require both a check and a save, IIRC, and level-based should be reserved for powers that use neither a check nor a save, since those are really ways of defining level's impact on the power's efficacy. You might use * for powers that have multiple possible effects, indicating you should see the book; or you might list each of the options under the power's heading with its own code in order to save that much time.
I also use another code to clarify what kind of actions are needed and what kind of concentration: m=move action, s=standard action, r= full-round action (because I also append an 'f' for fatiguing powers), and - for powers that don't use an action; c=concentration, t=total concentraint, - for powers which can't be maintained (i think i also had m for powers that last 10 rounds/1 minute without maintenance... haven't got my stuff with me right now to be sure about that one).
So a power might be listed with something like c/mc, or s/stf. The first requires a check, a move action, and can be maintained with concentration, the second provokes a save (requiring no check) and requires a standard action and total concentration, as well as a fatigue check.
Maybe something like this would be helpful for your player. In True 20, since all powers will have the same modifier (unless you're using multiple abilities to contribute, like in Blue Rose), you don't really have to list the bonus for each power the way you would in a system that used skill points (like the Psychics' Handbook version). That frees up plenty of space on a character sheet for a handy little code like this.
I hope these ideas can help you out.
No kitten is going to tell me what to do. I'll fall off this branch to my death if I feel like it!