I certainly agree with your sugguestions about the the option for a besieged city to surrender.

Most of my campaigns as you say often had me eliminating the army in a field battle and besiging the few survivors, who are often so few they couldn't even make a football team! Yet because of the "auto shooting walls" any assault gives you massively unrealistic losses and starving them out is not possible...

Hopefully the arrow towers will not be in RTW since we can now place troops on the walls... At least i hope to got they won't be in!