2.0.3 doesn't seem to have as many problems as 2.0.1 did, but there's at least a few going around.
The first is more of a problem players are having-- the actual code is "working as intended." More than a few players were distraught to note that crowd control trinkets like the Tidal Charm are now "fizzing out after level 60," according to the tooltips. Drysc says about what you'd expect: that this kind of stuff is part of the CC nerfing going on, and that the trinkets coming in BC will make your eyes pop out of your head anyway. Tough luck, basically.
There's a few known bugs going around, however. One a lot of people are dealing with is that the default target frame-- the little portrait of your target next to yours-- is disappearing. One small fix is simply typing /console reloadui: that seems to bring it back up for a bit, but it usually drops away again. It's definitely a repeatable bug, though, so hopefully a word from Blizz is forthcoming.
Another known bug leads to issues changing and promoting raid leadership and main looters. Blizz acknowledges they're working on this one. Meanwhile, Kelriia over on LJ supposedly has a fix: either type /promote [name of leader][last letter of leader's name] , or /script PromotetoAssistant [name and last letter again]. Not sure if anyone else has tested those (or why you'd have to include the last letter repeated), but if it works, there you go.
A few people are complaining that their addons aren't loading-- here's a quick reminder that after a patch, you have to go to the addon screen and actually check "Load out-of-date Addons." Worked for me.
And finally, just a personal disappointment, being a Shaman:
Where the heck is my Totemic Recall? Never mind-- commenter mubari says it's waiting for me at the trainer. Sweet!