The Bannerlord class system is like Overwatch, players have to pick a character. The Warband system is like CSGO, with customized loadout. Overwatch has updates frequently because it is much more difficult to balance the game with that system, but CSGO never has any update regarding its balance because its system is superior for game balance.
Warband system has 3 classes across all factions: archers(horse archers for Khergits), infantry, cavalry. Bannerlord has 7 classes for each faction: light infantry, heavy infantry, light archer, heavy archer, light cavalry, heavy cavalry, skirmishers, shock infantry, mounted archers. Many of the classes can be combined into one class(light infantry, heavy infantry). What's the point of all those very specific classes? The 3 class system can provide any possible role of the 7 class system, and it is intuitively easier to balance 3 classes than 7 classes.
Also Warband system can provide many more different combinations of armor loadout than Bannerlord, just do the math. Players like variations on the battlefield and feel unique, rather than identical to other players. The single armor value for head, torse, and leg in Bannerlord even limits the different combinations more. Even Mordhau has different armor value for different body parts. It just makes more sense for a swordfighting game. Even shooting games like CSGO has a head armor and regular armor.