Arrow carts makes sense since they shoot up and over. Catapults were always a cheap and far too easy method to defend a tower that costs a single person.
It was flat out imbalanced.
Also, massed arrow carts put out 10 times the damage a catapult could ever hope for. If you don’t know this you’ve never experienced a proper lord room meat grinder where arrow carts kitten people in mere seconds regardless of build.
This will just mean it takes 2-3 guys on arrow carts, which can be counter-sieged by catapults, to defend a door.
Also, this may be a surprise to most folks, but castle defense is not a desirable position. It’s desirable if a fight happens in the short term only. In the real world things like food, disease, morale, etc are all serious concerns and most sieges never made it to battle before surrendering. The attackers actually have most of the advantages real world.
However we play a game revolving around combat. Keeps are still a major defensive boost, towers are still a moderate defensive boost. You just gained more counters is all.
Also, word to the wide, keep that cata around inside to counter enemy siege
. Or a well placed treb at certain towers/keeps.