Patch 2.2, currently in testing on the PTR, has some great improvements like voice chat and reporting AFK'ers in Battlegrounds. What it doesn't have is any new, big, sexy chunk of playable content. So when are we going to see the post-Karazhan 10-main raid zone, Zul'Aman? New Heroic Badge rewards? Guild banks? Oh, we already know that last one.
Forum MVP Schwick on the WoW European forums has compiled a list of known updates in Patch 2.3 and beyond. He often provide reference links to his sources form many of his future patch notes, which makes him an information god in my book.
He also goes on to list all the verified information about the WotLK expansion. I thought I had read all the info that was out already, but on Schwick's list I found items I didn't know, like the fact that Blizzard has a plan to deal with the fact that the Horde doesn't have a fear ward. Or that Naxxramas, the last raid zone introduced before TBC launched, will be repurposed in the new expansion. Or that new shaders will be introduced for shinier graphics. Mmm, sparkles.
Check out Schwick's post if you want to get a look ahead about what's known for future patches.
Screenshot of Zul'Aman boss models courtesy of MMO-Champion.com.