To be honest, armored mages has never been a big concern of mine. It's relatively easy to do with one of the dwarf sub-classes and Githyanki, but it doesn't concern me much. Especially in this edition where clothes, light, medium, and heavy armor can all get into the 20s on AC if you make the effort. A mage in armor is going to ameliorate some threats, but really the best defense a caster has is non-casters.
Ideally, my wizard never takes direct physical attacks, but having a decent AC frees up spell slots for other things. It's not OP or anything.
