Silly concept, but honestly, I'm still surprised it hasn't been done yet. Arc 1 worlds at least.

I could see it now:

Wizard City = Headmaster Ambrose
Krokotopia = Krokopatra
Marelybone = Queen Vicorgia
Mooshu = Emporer Yoshihito
Dragonspyre = Malistare

Maybe a few wonders too:

Ravenwood School Of Magic
The Sunken City
The Krokosphinx
Tomb Of Storm
Digmoore Station
Katzington's Lab
Royal Museum
The Jade Palace
The Great Spyre
The Tower Archives

Unique Units even might be possible:
Skeleton Soldiers to replace the Pikemen
Novice Sourceror to replace the Scout
Queens Guard to replace the Riflemen
Ninja Pigs to replace the Longswordsman
Krok to replace the Warrior

We're sitting on a content gold mine, people. At least consider the concept. If we can have Pagan Min from FC4 and Stalin fight it out, Wizard101 characters don't sound too far off. Then again, we could use a Leader Changer in general, not a Civ changer but just the leader. Nevertheless.