I've had this problem since PB2. Finder does not load - no system errors. The only sign of a problem is Force Quit Applications indicate Finder (not responding). Restarting will make the Finder icon pop in and out of the task bar - but never loads. (Mac Mini 2012 i7) Would really like to figure this out instead of going back to PB1.
Testing in a new User will quickly tell you if the problem is system wide or if it's your User's folder that contains the problem.
CREATE A NEW USER
Go to System Preferences --> Create a New User in Users & Groups.
Switch to the New User by logging out/in or use Fast User Switching.
Only default Apple apps will be in the Dock in the new User. Go to Applications to open other apps you might want to test.
Do you still see the issue?
If yes, then the problem is with your base files.
If no, then the problem is in your User's folder.
Once we determine if it's in your User's folder we will discuss options to fix.