Fortunately for us KotOR fans that really enjoyed the single-player RPG and story associated with K1 and K2, BioWare and LucasArts have put a very strong focus on story development in this game, and are probably on the way to revolutionizing how MMOs incorporate story into gameplay. They even call story a pillar of the game, meaning it wouldn't stand without it. That means we will get some great story, from the same writers who came up with KotOR, and I'm sure we'll find out what happened to Revan and perhaps the Exile as well (although she wasn't a BioWare creation). As I mentioned in another thread in response to your somewhat-coherent rants, the SWTOR.com website has already dropped some tidbits about the Revan continuation that lead one to believe there's lots more to come.
Well, I do think they will allude to it if in a minimal fasion.
Drew Karpyshyn has made minor references in his Bane novels to events that unfolded in K2. I.E. (Paraphrase) "Whoever had been here (Nadd's Tomb on Dxun) before had missed a passageway, presumably hidden away by sith magics." --That's where he "Acquired" (in a certain sense) the orbalesk armor and found the holocron of Freedon Nadd.
I'm sure there are possibly even more references in the novels if you look carefully enough. Point being: if Drew K has made reference to TSL events, and these books are canon...AND he is working on the storyline of TOR...there is a fair possibility K2 events will be mentioned and that it won't necessarily be retconned out of existence...but perhaps crammed down, put into a box, and shoved into some far off corner since nobody else really was in a position to know what went on at that time, really.
Nihilus also had at least one other other apprentice (
http://starwars.wikia.com/wiki/Unidentified_Darth) besides Visas. That was how the "Darth" title apparently survived after the fall of the Triumvirate. So, if "Darth" is passed on (which we know it will be) then this particular sith lineage may possibly converge upon this next game. Or it may not. (shrugs) According to the 'new essential chronology' this is how it is. It had to become prominent once again in order to die out again by the time Kaan's dark brotherhood is around. Point: This is evidence of Nihilus and therefore K2 having happened.
Anyone who has read the novels knows where Bane got his "Darth" title, and I won't spoil it here.