Combat is not too bad. I think there's just no appealing rewards for keep playing MP. You just get simple badges as you win more. Need better rewards to encourage people to play MP.
And no proper competitive scene established. Something like ELO system should be used. Newbies get dominated and helpless agnst warband users. The problem is playerbase, it will take ages for matchmaking with current playerbase. TW should come up with a good idea to attract gamers.
I know it's in EA stage, so hope things are ready when EA ends and officially releases.