Isn't that pretty much what 5e did? There's like what, 2 classes (maybe three if you squint) that don't actually cast spells at some point? Even many fighter subclasses get spells or spell like effects.Mmm... sounds a bit like to solve the problem that spellcasters have the edge over martial then let's make all martials spellcasters
D&D has solved the divide by just making everyone a caster.
I haven't seen a straight up non-caster character in the game in so long I almost forget what it looks like.