First post here on this Forum but have played PW since 2012/2013 from time to time, mostly as a doctor.
Anyway, I agree wth Ironhawk, I'd also go for a basic class system and instead of making custom classes, maybe add a couple new ones
(like builder for example, if basebuilding or something similar would be possible in Bannerlord) ?
I also don't like the loading bars for training very much, though I understand that the Warband engine seems to be a limiting factor in many regards.
So in Bannerlord, instead of loading bars for the class training, how about putting in something that looks a bit like the Tutorial from Warband and call it a "training field" for example ?
Like add a couple archer target practice thingies for the archer and crossbow class training and scarecrows for the soldier classes.
In order to become one of the mentioned classes, you have to shoot a couple times as an archer, hit the scarecrow from every attack direction once or something like that. Or to become a farmer you have to harvest one wheat.