If the single-player campaign is solid, I'm looking forward to it - because it's multiplayer is completely dead. Creating and maintaining a critical mass of players is incredibly difficult in such a niche genre, and 18 game modes is positively absurd for a game that likely doesn't even have 18 players log on to check for activity each month.
The problem Overload had and still has to this day is branding. I've met countless people who don't even know about Overload, but they've all heard about the new Descent game coming out this year. It's a shame to be honest, Overload is such a good game. Unfortunately this might be a problem for player retention if D:U turns out to be crap.