I just recently got back into LEGO, and was really sad to hear Kingdoms might be leaving (though I am a big LotR fan). I did some looking around and found this post on a blog. Basically, in a conversation on Twitter, LEGO says Kingdoms is not ending, and there will be more sets in addition to Joust. I looked at LEGO's twitter myself and found this, also:
So if I'm understanding all this correctly, it's most likely we'll see Joust plus a few other exclusives this year. Am I right?