I watched many player's video about siege , I find that the wall isn't really vary useful in defense ... because of the "Trebuchet".
Trebuchet can fire from outside but there is no way to fire back from the defenders .
In my opinion , the real castle wall can set the Trebuchet on it , the defender can fire it at a higher place , and fire longer than the attacker , this is more seasonable for player to defense their own . and make the attacker hard to attack , because they have to get into the fire range of defender.
And , I think the siege weapon should be more multiple , the Battering ram , Siege tower ,Ballista , Catapult.
still another one thing that I want to see in this game , the Drawbridge , much better than a gatehouse I think ...