I have not played helms deep yet, but i really hate ishtar and burg, and here is why.
Attackers have to run too far, too few ways in, too big maps, not enough access to gatemechanism, breakable doors everywhere, bottlenecks, no good areas for fighting
Defenders cant access their castles properly, too big maps, too far to run, not enough access to gatemechanism, bottlenecks, no good areas for fighting
So what to do..... maybe blast them with a shrink ray and make them smaller, move attacker spawn closer, redo gatehouses so you can enter from below, add ladders and shit inside castle so there are more than 1 or two ways to go. Ladder acess to walls from the inside, and giving attackers a way to get down, having some way for defenders to leave flag area at all would be nice.
Right now its alot of running and running and running and hacking doors and hacking doors and hacking doors and a huge clusterfuck fight where you cant move and then one team wins hurray.