I can pretty confidently say that the class system isn't the main issue stopping new people from playing, but the amount of trouble it seems to have caused TW itself in terms of balancing and creating new modes seems like they shot themselves in the foot.
It would be nice to have a customizable loadout and would make BL MP a bit more unique, however it's still likely that they'll never change that. It seems to be embedded really deep in their design and codebase now. If they're going for a class-based system though, they need a complete overhaul of the current system. For me personally, hardly any class have a unique play-style, there's just ****tier versions of ****ty classes. For instance the only heavy infantry that I'll even bother to pick is the Oathsworn, and then the Varyag which just feels like a ****tier oath sworn. The Menavlion Infantry or Voulgier are the two big dogs of 2handers, everything else is just a cheap knock-off. Other than those, I really only choose the peasant classes as they're almost fast and nearly fun to play, and all of the peasants bow down to the Battanian club and pike man. Not to say that there shouldn't be dominant classes, but there should be more nuance to each class.
I think if they're going to keep the class system, the Perk 1 slot for almost all infantry should be a wide selection of weaponry. You should be rewarded for doing well by being able to choose an armored, tankier class, but you shouldn't have to choose a bad weapon just to play as that class. While on the topic, I think each team should get a dedicated spear infantry class that has a high movement speed (spears are actually alright if you can outmanoeuvre your enemy, but become **** as classes like legionary)
All in all, loadout system would be much better. Probably won't happen, so at least fix the ****house class system.