you can blame and mock nasu all you want
but 75% of the roster it has, both men and chicks, look either cool or battle themed, they aint looking like weebs, thats the harsh truth
It's honestly funny because you can say that for some of the character designs but he atleast had the tendency to get character designers that knew how to make characters pop even when they look basic:
For instance, there's nothing unique or insane about these designs, they are actually pretty basic but here's the key:
It still fits the personality, the overall touches of what they are and still manages to be memorable and that's the true key to making a character that looks mid and a character that can be remembered.
Let's be real:
No one is going to remember Touma unless they go truly all out in making people care... it's literally the same issue with Saitama too. But people will remember Mob because despite how he looks plain, he still has a look that works for his character and personality.