I beat Chang Ban the exact same way i beat Yi Ling, except i didn't even defeat the rest of the enemy army first :)
I cleared out all the gates in the south-west corner of the map and i _think_ all the sub-generals. The rest of teh allies were swamped with enemies but my area was mostly clear... except for Cao Cao himself :)
I stood next t the last gate i cleared and slowly sniped him down to nothing. This was a bit harder than it was with Liu Bei because every so often an enemy archer would show up and start shooting back and i would have to take him out, luckily it still didn't tip off Cao Cao as to where those pesky arrows were coming from :) I was getting kind of worried that i would run out of arrows before i finished him but he finally keeled over when i had about 10 arrows left. Yay!
In other news, well, not really, Zhao Yun is cool. He doesn't have as good crowd control as Sun Shang Xiang, but he does better against individual generals. It's easier to deal with enemy generals if you can get them away from their allies, but it's even easier if you can get them away from _your_ allies. I've gotten pretty good at keeping up a continuous attack on generals without actually knocking them down, but as soon as my allies show up they disrupt things.
It's _especially_ annoying when they charge over on a horse and shove me out of the way, but even on foot they'll run in and do a knock-down maneuvar and cause the general to get his health refilled or some otehr bonus, or even more annoying they'll shove him back a little out of range of my attacks but not actually make a successful attack against him, letting him start a combo attack which ends up flattening me =P