I think we can agree physical is more brain dead, but if you need to think more round per, you're being more tactical.
Summons can easily take advantage of available elements, surface creation is part of the caster package. It's clearly a flexible pick. I'd be hard pressed to run a caster team that didn't have the one physical guy, even if he was necromancy and summons. That has more to do with wanting the variety of damage types so I can exploit all the weaknesses, than specifically needing that guy.
I still say there's so many possibilities with magic that aren't worth giving up, as long as you don't dump all those expectations on one guy.
