I agree, boiling oil or something more useful for castle defense would be great. As it is currently ramming through the gate and pouring men into the castle is the easiest way to get a siege finished. Towers burn all too often and ladders are horrid unless you use them in cheesy ways. It would be nice if at least stones could be dropped onto the enemy whilst they are entering the gateway whether to ram or simply enter, as long as the gate was still under the defender's control.

Tschüß!
Erich