Outlands is fine. I really like the Outland areas and dungeons. It's Northrend onwards I really don't like. It's probably because I have just done them far too many times. Thankfully all 10 of my characters are 85+, so I won't have to do those zone again (at least until the next race / class is released).
Now if only I could get motivated to level in Pandaria... I truly cannot stomach another run thought those zones.