I come from WH I where defense towers are actually a crucial part of a siege defense battle, but now that I've started WH II, I find that they seem to be quite useless.
In WH 1, even the lowest level towers have a good chance of destroying at least one siege tower if you use it right and focus fire. But in WH II, it seems that no matter what I do, there is no way to even come close to destroying any of the siege towers, and this really ruins much of the fun for me.
I tried using two of the highest tier defense towers, plus two blessed trebuchet artillery, to focus down one siege tower, but couldn't even bring it below 50% when it reached my walls. One volley from both my trebuchets units only does 1% damage on the siege tower, this makes the siege tower 16 times more resilient than even a defense tower WHICH MAKES ABSOLUTELY 0 SENSE!!! How can you build a make-shift tower in potentially just one turn and have it be 16 times stronger than the defender's towers, when the defenders literally lived there all their lives???
Some might argue that in WH I the defense towers are over-powered. However, I believe that in WH I it is actually pretty balanced.
Certain positioning of siege towers can make it much harder for even a tier-4 defense tower to single-handedly destroy it, so it encourages the defenders to choose if he wants to focus his fire from multiple defense towers, this and which targets to focus on.
Attackers can counter this by, in turn, focusing his siege towers in a few locations that he deems most important, so that even if one siege tower falls, the others are close enough to breach the wall. The attacker can also use mobile or expendable units to distract the tower and buy time for the siege tower to get close enough without taking too much damage.
The defenders can then rearrange his troops so that the best melee troops can take the brunt of the concentrated flush of enemies and position the archers where it is relatively safe.
The attacker could also potentially invest more time in besieging the city, so that he will have more siege towers in battle, or if he's in a hurry, run the risk of having all siege engines destroyed.
You see that there is a lot more room for interplay and planning here.
Alternatively, the game designers could potentially make it so that you need at least tier-2 defense towers to consistently destroy enemy siege engines, this would incentivize players to spend resources towards upgrading their walls, unlike in WH II you just don't bother because it makes no difference anyway.
Let's look over to the interplay and mind games of the current WH II system.
The attacker doesn't need to even think about what he needs to do, he could just put a siege tower literally anywhere and it's pretty much guaranteed that it will reach the wall safely. The defender doesn't even bother to try and destroy the siege towers and just sit on the walls wondering why they even spent %60 dollars on this game.
The attacker may even line the walls with siege towers because there is no need to concentrate or even consider the positioning of the towers, and the defender is left to wonder why he even built walls in the first place.
The attacker can even push a siege tower face-to-face with a defense tower, completely blocking it off and rendering it useless. This trick I've used on multiple occasions in WH I, but pulling it off requires quite a bit of skill and cunning, because if I didn't play it right, there is the danger that my siege tower would be destroyed by the enemy defenses before I could reach the walls.
Now however, there is absolutely no point in guarding the walls, and I've on multiple occasions considered straight up abandoning the walls and just station my troops in the city, where my Bretonnian knights have a much better advantage, as compared to on the walls where my peasants have no advantage and every disadvantage possible.
The attacker has 0 risk in the process of breaching the walls, he doesn’t need to consider how much time to invest in building towers, because he is guaranteed that all of his towers will reach the wall anyway. It might as well be a non-siege battle, except the enemy is confined inside the fortress and his mobile troops cannot freely move around. The walls have become almost a detriment to the defender, which begs the question (again): Why the F*CK do we even gain from having walls?
I really hope the devs could really buff up the defense towers in WH II, because I used to really enjoy playing siege, both attack and defense, but now, it's almost not fun anymore.
(I’m considering going on multiplayer and abuse the crap out of these siege towers, use them to block off every defense tower, hopefully this will ruin the game so much that it generates enough attention for the devs to realize just how broken the current siege mechanics are. If any youtuber sees this feel free to use my tactic and make tones of videos about it, I believe this can help us all in the long run)