Sticking to siege towers and ledders for castle attacking and catapults only against the troops.
Sounds fine, I don't mind ladders apart from there only being one. I'm not a fan of the siege towers though (they're meant to provide protection, but instead leave you more vulnerable).
Yeah, I have to do something about this ladder-siege tower issue. Siege towers have to be made more effective than ladders. Not sure what do do though.
Anyone with a good idea is welcome to post it. I'm not planning to add more ladders though. It would be a lot of scene building work which I'm not really interested it.

I can just imagine your machines in this scene:
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What's this from? MaB Realism? Really impressive look.
How's the trajectory for non-explosive ammo? I'd imagine the defenders are pretty hard to hit on the walls.
I have no idea how accurate those siege engines have been in real life, but indeed I can't make them too accurate.
When hitting a wall I'll give them a certain area damage: When it hits the wall, I trigger a particle sytem with some rocks flying around and if it hits at the top of the wall with the merlons near it, near agents will receive damage which would be caused by those stones maybe in real life.