I agree the battle timer sucks in a city assault.

In my greek Campaign I hated City assaults, because of the inherant slowness of Phalanx meatgrinder combat and movement in the streets.

Granted I can remove them from the formation to run them, but the AI is very adept at choosing that moment to launch a cav charge before my men can reform the formation.

In a large city it just takes too long to assault.