Some good discussion. I'll go on record stating that I am definitely in favor of adding the ability to control gun towers and the gate, and giving the gate a locking mechanism.

Sure controlling towers would make the game easier, but it would also force the player to make choices. Do you attack the ram or the ladders coming at you? Perhaps something that would even this out a bit is not being able to control each individual tower, and that you have to pick a single target and all towers in range will fire at them. Any other towers that can't reach the target unit will go back to autofire and engage at their own discretion.

Regarding the gate, I have the same complaints as the OP. Adding a means to control this would be a godsend, but sapi and the others had some good points. Let's face it, the pathing in this game and the blobbing isn't that great, at least as of v1.1, even with Carl's great patch. I think there's a few key points to the gate mechanic, at least as I see it.

1. Give us the ability to lock it, if not open/close. I'd actually prefer just the lock instead of manually opening/closing it.
2. The lock function would immediately close the gate and lock it. Anything caught under it should be instagibbed.
3. Anything caught outside after the gate is closed , such as split units, would either force the game to A> keep the split units at the gate or B> dynamically split off the affected men from the parent units and treat them all as routers, and route them off the map away from the nearest enemy. Given my experiences so far with the TW engines I kinda doubt the latter is possible, so it might just be the former and you're stuck with your units massed around the gate.

Just some stuff to consider. Whatever happens I still think CA needs to put some serious effort into unit cohesion, blobbing, and pathing. Hopefully 1.2 will be a good step forward.