LEGO Universe died because it was everything about LEGO except building.
Here it's going to be about building, but no one to play with. Genius.
Hopefully they're serious about that "yet", and multiplayer will be added sooner rather than later. Then it's just a matter of getting the building part right. Interacting with other people will just happen on its own. Of course, I don't see this making the smart move of full open world MMO with no instancing. Without that, it can capture a decent audience for a long time, but it won't have quite the same broad appeal.