Could be some addon.
Move your WTF folder out of the WoW folder and try starting up the game like that. If it works, then put WTF back in, and start disabling addons one by one to find out which one is the culprit.
Could also try the Repair Tool from the launcher, I suppose.
I have a Macbook Pro. I was having issues for awhile where it would randomly crash every 5min after 5.2 Try going to your chatbox (if possible), right clicking General. Go to Settings, and find "Battle.net Whispers" on the first tab and uncheck it. That might help. Also make sure all addons are off. You could try deleting your Cache too.