Yeah, I feel like some of the "power source + role" stuff felt a bit forced.

In retrospect, I think that's one of the weaknesses of 4e - "here's a structure, let's push everything into it." I personally had hoped that fighters would end up with stronger at-wills and more of them, so that their gameplay was more like "choose the right move for the situation" while wizards leaned more on dailies or encounter powers. That would keep the same general structure, but allowing for more variation within it.