Mercule
Adventurer
Not sure what you're getting at, since that supports my point that casters get their abilities differently than other classes.Unless you're a caster.
Here's the wizard's options at first level...
Do you think the system might be starting to collapse under it's own weight?
Spells are spells. They aren't expected to be anything other than stand alone rules exceptions. You could make fighters work more like casters, but they'd play a lot differently -- most likely in a way that felt more magical, like the Bo9S.
As I said, you could do everything as feats, but I really don't think that'd work out well for a variety of reasons.
4E hit something off a middle ground, but something about it didn't resonate with enough people.
That leaves full classes, which I think add a lot of weight because each is expected to have a fairly unique set of abilities that fill its levels. What might work would be something like 1E Oriental Adventures, that provided a complete new list of classes. I'm not suggesting that there are several variant PHBs. But, there could be relatively focused theme books that are intended to be included our diagnosed as a whole. The problem would be having something with enough depth to warrant a full rule set but focused enough that it would be more than a big list of more random options.