The Heroica theme will be a subtheme of LEGO Games. It was present at the 2011 toyfair (
Eurobricks of course).
Of course, I'm pretty certain that there are not stats or special dice (so it couldn't be like D&D), but it's a very interesting idea. I hope that it turns out to be a good one.
I see a LOT of weapons from each game (in fact, a full array of excellent ones, including many newer molds), as well as many 2x2 jumper plates in new colors. There appears to be a new door piece (although this could just be the old grille for the window). The dice look quite interesting-they have double-thingies and could prove very useful in other things.
I have sworn to completely collect two many themes this year (Pharaoh's Quest, Alien Conquest)-but I will swear that I must get these-the adventurer inside of me wants it!
I'm a bit dissapointed about the builds, but I guess that will save money. And these are prelims I think (since they're ToyFair)