-Reigns' first two WWEWHC wins. If he was going to have a WrestleMania main event moment against Triple H, why have him win the championship twice before that? It devalued the moment. You give it to Sheamus, a guy no one cares about anymore. Then he wins it back on a random RAW episode, and loses it at the Rumble. Makes no sense. I would rather Reigns just win the title at Survivor Series, Sheamus fail at his cash-in attempt, have Triple H win the Rumble match, and have Reigns retain at Mania. At least make it mean more when he gets there.
-The Rock's title run in 2013. I understand the reason behind it, but Cena-Rock II had nowhere near the heat of the first one and we all knew Cena was going to win. I would still have Rock announce his title match in advance, but instead, have the match take place at WrestleMania. Punk would still turn heel, Cena would still win the Rumble, and it would be a triple threat at Mania where Cena wins.
-Ziggler winning the WHC in 2013. It meant absolutely nothing and creative screwed up the story amazingly.
-Del Rio cashing in MITB at SummerSlam. You could have just had Punk beat Cena clean at that event without the Kevin Nash crap and have him keep the title until WrestleMania XXIX where Cena wins it back. Punk's momentum just came to a screeching halt after that mess.