Massive Bottlenecks of Stupid linear questing (See:Ophidophobia) cause most of the casual server to lose hair and sleep and reduce general chats to namecalling and terrible trolling.
All initial 85 content done in first week of play including raids (altho probably not heroic raids on Dala).
Arena/BG season gets pushed back
Horde Dominates Tol Barad.
Alliance pvp Guilds promptly transfer server and/or faction.
Im sure i'll think of more
Feel free to add your own
btw Can we get Winsome to do those weekly or monthly raid updates for Cata? I think that was my favorite thing on the old Dalaran forums (during WoTLK that is).