How awesome this game is and how easy it may be to improve, I don't think there will be a castle crashers 2. It's been like 2 and a half year, but there's been no indication that there's a sequel being made, while most developers would have announced a sequel if the first game was such a success.
The Behemoth is working on Battleblock Theater right now. There definitely isn't going to be a Castle Crashers 2 coming out any time soon and it's unlikely that they'll ever be one at all. --- http://i51.tinypic.com/6pszrt.jpg GT: Lydonious