That sounds cool, a much more refined version of my suggestion.I'm experimenting with an even less restricted paradigm. Powers have an associated source, but you don't HAVE to be attuned to that source to use the power. You simply have to be attuned to it to drop RIDERS on top of it. That is, you only have riders from your source, and you can't spend power points to enhance an effect (which is basically just a slightly different way of saying "get a daily use") without that attunement. So, a fighter can unleash a really potent "Spend a PP and add a rider to a basic at-will to make it into awesome thingy" and a wizard could still access the basic 'at-will', if they have the right boon, they just can't pump it up. This cuts WAY back on the numbers of powers required, and pretty much provides the equivalent of hybrid/MC. You can always try to become attuned to several power sources if you want, though you only ever get the class features of your actual base class (which generally includes your role-defining riders).
Its an experiment, but I THINK it will work, and basically the result is kind of a bit 'covert', but its VERY close to identical to classic AEDU in effect, except you use power points to get your encounter/daily type effects. The PPs can double as HS and AP too, so you don't really want to just burn them casually. OTOH it does open up the possibility of spamming a specific potent power/rider/enhancement combo somewhat. I guess that is just sort of the price of admission though.