Some people who form like the 10% of the playerbase, skirmish and siege, the backbone of the population, are both nearly dead. Classes are dislikable. No good arguement has been presented yet.
Lack of custom servers is more of an issue than the class system. Most players who came to the game back in April had NEVER played warband and wouldn't know the difference. The main reason why people left the game is that siege (the most popular mode on launch) crashed nearly every game. Nobody is going to play a multiplayer game when the servers don't even work. Taleworlds really screwed up the MP launch with this, and it's mainly their own lack of effort. Siege was only live for about 2 weeks in the beta before EA launch and never was performance tested as it should have been.