Okay, so here's the thing about all the talk about tearing down casters: as much as I am a fan of deleting the wizard, casters lost all their fiddly, annoying restrictions so as to allow their players to be able to play the fantasy of being a wizard and not the world's worst gun. That and to offer the experience of a pop culture wizard while desperately holding on a legacy casting system from a specfic novel the creators really liked that doesn't mesh with any other pop culture wizard.
The main problem here vis-a-vis martial characters is that once they got their fantasy, the wizard players who would become designers pulled the ladder up after them and now simply refuse to let martials get the fantasy, hiding behind the fig leaves of 'simplicity' and 'verisimilitude' and 'just give up and be magic already'.
DND would be a lot more interesting if it embraced the Dying Earth magic system more deliberately. So much design fodder in there to build classes around.