that would be way more tactical, let the CIV play one unit, after the other, you, ai,ai,ai,ai, you ,ai, ai, ai ai, you, etc.etc.etc.
Aldo, that would become painfully boring too....hahaha
Anyway, aldo there are many types of units in CIV, most come down to to a few types of "skill".
Spear/sword/inf = melee
arch/cat etc = ranged
Cav/tank = attack forces
So it ain't too hard to work out move/battle mechanics for each "category".