Two ideas I had for siege equipment used defensively (one passive one active). Archer stakes would be nice for archers to deploy in front of a their camping position, this would stop horses from being able to pass through them (don't even need to make horses take damage on them, although that would be preferred). I'm thinking of this in the primitive style of cutting down a few thicker branches and making them into points.
And a more active "defensive" siege equipment would be for actually sieges, especially strategus, something you dump or drop from the walls onto the enemy. Like how lots of castles had murder holes where they could dump molten liquid down, maybe have something you can drop over the walls to harm enemies below?
