Its also the maps design that allows cav to reach all points on purpose.
+1
As a Warband Siege Clan Player let me put some input here:
Cavalry on Siege was also a thing on Warband either for solo behind the castle sneaky ladder action or as soon as the gates have fallen to rush the flag. However there were a few fundamentally different things.
First: what Apri said.
Second: There are no behind the castle ladders for sneaky action where you have to leave your horse behind.
Third: Several Flag System. While the several flag System has its action oriented benefits there are some drawbacks. The Enemy Spawn closes on to G with Flags taken. Attacks dont have half an hour to take castle but like 5 min to take a Flag. and this results in point four.
Four: You cant take back the Gates but need to retreat and defend G. In Warband you had the chance to take back the Gatehouse the entire time but not in Bannerlord with its forward Flag Spawning. While it is logical and entertaining and exciting to retreat and defend a easier to defend position (which is not always the case lol map design oof), you cant close the gates anymore for Cav.
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Now lets talk a little bit about map design.
Warband had a lot of fan maps, but I will leave them out.
The native maps like the sandcastle or the castle in the mountains had several cav stopps along the way. One the gatehause falls you can get in with the horse but you wont get far. There is either a HUGE stair along the way or another barrier for Cav. There where some native maps, especially the oldest, where Cav could go right in after the gatehause fall. However the Gatehause was heavenly garded and it wasnt a brakable wood door but iron you had to open and close atop. Undestroyable. Take back the gatehause and close it. Cav is stranded.
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Now Warband Custom Server had a Classpicklimit.
Which was great because Inf is the bread and butter of mount and blade. A Cav roaming the spawn in Warband, like what happens in Bannerlord, wasnt possible in this extand, because you will just get yourself killed pretty fast. In Bannerlord you can either Cav swarm the attacks Spawn and wipe them out while defendkatapults destroy attackers siege weapons. And you can swarm G with defend or attack Cav to either defend or attack it, because it was more effektive then Inf. Warband had something like a 50% Inf, 35% Archer, 25% Cav limit. As an advocat for Inf only TDM i would ofc support this. But the fundamental problem is another.
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Now to take a little history lesson. Bannerlord isnt actually that far off.
You have almost no Cav as attacker at Start and when the Gate falls, Cav swarms the City (or castle yard). While the Defenders go out with Cav Charges to Defend, while they still have that advantage on open field. The difference is what happens between the castle yard and G the palace. While you can go with your horse from the yard to the throwm room (like in Warband) you can go all the way to G with your horse. And where the Problem startet with what apri said it also ends with it, because the map design favors cav. Some on skrimish as well. Positions where Archers are save for Cav makes Inf more valuable to push that Archer. While is sure gives the ARcher class a huge buff, it will need a debuff somewhere like less HP (like Warband) but that is a different discussion for another day.