1. Killing the Nexus angle the way that they did.
2. Badass decay (n): When a once fearsome character is turned into an easily beatable opponent. see example: Kane.
3. Too many face/heel flips with the same characters. What if John Cena turns heel? What if the Miz turns face? To name a couple of different ones.
4. Speaking of Cena...you already know where I'm headed with this.
5. Eliminating most of the in ring moveset. When's the last time you saw a piledriver? A decent hurricanrana? A sitout powerbomb? Just because a few guys don't know how to take a bump, they shouldn't have torn the wrestling move handbook down to a couple pages.