Elindor, the thing about atacking a wall with a gatehouse, is that 2 ladders are never enough, there has to be another way in besides de BD, (this also depends onthe size of the castle ofc.)
I like it, dont see why it shouldent work, standard siege castle type. Id work on the visuals a bit more tho, i dont like seeing trees growing inside the walls, neither i like to see beautifull patches of green grass instead of mud and grass.