Another option your post made me think of is to do something similar to what PF tried with their mythic rules. You could have a set of options that are strictly buffs, but you don't have to use them. So you can play your Fighter* as is 1-20, or you can add a Paragon Class at level 11 and explicitly give your character a "supernatural" buff.
Maybe I missed it (or I read what I wanted to see instead of what was there), but I didn't think the OP was about keeping up with casters. I was more about the flavor or a martials abilities.
So only casters get a power fantasy. Otherwise you're a town guard +1. Toughest guy at the gym should be the level 1 starting point. Hercules should be around level 15 with battlefield altering feats of strength and power.
I think that point is that those characters in comic books and anime are nonmagical in name only (NINO?). They are in fact supernatural, so why don't we just be honest?
They aren't supernatural.
That is a matter of opinion, not a fact. Not everyone wants to play that game or for D&D to be that game. I do wish D&D would accommodate both more explicitly.
They are not called supernatural, but in fact they are. People in comics and anime do things that are beyond the scope of reality. For example, a common idea in anime and mange is that a warrior can move so fast they create an after image. That is not reality, it is fantasy (aka supernatural - or at least how I am using supernatural in this context).
Like, maybe they can not level their town guard up if they want to fulfill some kind of impotence fantasy. I don't know, I just know the existing martials are underpowered in terms of heroic fantasy compared to casters. Some people really want that BMX bandit feel, but I don't think letting them hold whole classes hostage is fair.
