Oh my god this mechanic is awful.
And i think it wasnt some game design mistake. It was done on purpose so player just cant defend castles.
1) AI atack only when he is 100% sure that he can win no matter what.
1) AI build siege camp instantly. so you have less time to reinforce, almost no time. I Warband i can go through half of the map to defend my besiged castle.
2) No defensive tools, no catapults, no ballistas. You can try them in custom battles, and they are completely useless there. They placed in such place, that you can kill with them may be a few guys. For that you can use a frkn bow and kill 5 times more.
But that in 250 v 250, in huge battles AI loves to make a blobs and stupid decisions, thats why they cut them from defense. Becouse what if player can use it smart? No, we cant allow him to do that.
3) To cut your already small chances to zero, they did two things
a) That stupid mechanic that cuts your army in half when you want to help. Lol, i can cut that atacking army to small pieces with zero casualties, but for some reason i need to sacrifice half of my troops to get in castle. You can say that it is just bad game design. Okay.
b) If you already in the castle you CANT defend it. You can only kill half of your army and run or fight in open field. And you cant argue with that.
It has no exuse or explanation. Exept one - devs just dont want you to hold your castles without army of vassals.
Now to atack:
Most of siege equipment has two purposes:
1) To exist
2) To look cool in trailers
Fof example onager(non fire) and trebuchet. All you can do with them is destroy parapet(it can be useful for archers, but for some reason archers jsut dont want to be archers in campaign sieges) and kill like 5 guys with boulders. It cant destroy walls, becouse destroyed wall is a another map with new fortifications and camp points fof AI.
Balista.It was ment to be useless or was nerfed to the useless state. It placed very very far away in the worst possible spot. It is very innacurate for such rdistance. And becouse it wasnt bad enough, you cant zoom. You can zoom with every weapon and even without it, but not with Ballista. Becouse player will be able to snipe enemies! We dont want it! We add ballista not for this.
Yes, you can actually kill with that, but only for one reason - AI is very dumb. Becouse bots can actualy block that shot with shield. And not only one, but many. But again - just use a frkn bow, it is 100 times better.
Battery ram - very useful thing. Build it, set up on battlefield and forget. Becouse it forces AI to make a shield blob and it leaves walls less defended. Dont send your troops to the gates, becouse they will only smash this shield wall with no to little effect.
Siege towers. With ramp - good thing. With ladders - useless. And
never, never ever climb there!
Fire onagers. DAMN they are good. Only weapon that i see as an advantage when i build it.
So what we need to see:
a) They nerf fire onagers. It means that siege uquipments should be useless. And they made all of it for purpose(to not allow player solocarry).
b) they buff anything else. It means that it was just a bad balancing\realisation. And its okay, it is new game, it is impossible to balance it so fast.