Vaalingrade
Legend
First, I don't really care what casters have at this point. Balance can come later, but the current and most important facet is getting martials, fighters especially an opportunity to do something interesting and fantastic things.I know this isn't your position specifically, but I can't seem to connect the two ideas that "martials need to be powerful enough to feel fantastic" and "casters can do everything martials can and more."
Not that they're opposing, but it feels like one can interfere with the other. If martials can move mountains, casters can as well, simply because they can cast True Polymorph or transform into a creature even more powerful. And while you can say they do so limitedly, apparently that argument isn't enough.
Also, the beauty of the broken system that is 5e is that the caster can never gain feats of class features, so even if they're a dragon, they can't grab a goblin by the legs and beat his buddies with him. You know, if the fighter would ever be allowed to have the kind of fun.