The reality is they went the wrong direction in MP, and, while it may have looked good on paper, it really sucked in game, and 95% of the beta players told them so. I will give them kudos for trying something new, but they should have accepted it wasn't going to work and perhaps the beta players had a point.
Stances and block delays seemed like a cool idea. This would allow good players to master timing, and definitely would make dueling between two 'masters' more interesting. But in actuality it was just annoying. Game play had to be slowed down so people would have a time to react and use stances, but even with the game as slow as molasses a regular player still can't fight their natural reactions in blocking and hitting. Plus it,s not often you are in a duel, usually you are fighting as a group and with swings coming from all directions you just can't calculate your position and stance to counter (well, some people can, but they are autists).
Flag system in siege seemed like a really good idea, saving the attackers from running so far and the defenders from having to wait out a timer. But it just led to frustration as the defenders would never know quite where they were needed, and once a section was captured you could not recapture it. Warband sieges were a lot more organic with pushes and counter-pushes, plus the defender cav could keep busy trying to stop attacker reinforcements while attacker cav defended their reinforcements. And honestly it's not so bad to have little breaks after your death.
As for the class system, I see no justification in it. I have no idea why they wanted to take all individuality from the game. Like, really guys, WTF?