#4 Daniel Bryan loses against Brock Lesnar
WWE has a long history of using WrestleMania main events as a platform for feel-good stories, like Hulk Hogan reigning supreme in the early years of the event, Shawn Michaels realizing his boyhood dream, or the Stone Cold era getting its start after Steve Austin pinned HBK. The story of Daniel Bryan beating the odds to overcome Brock Lesnar and win the WWE Championship certainly would have fit that traditional mold. However, it isn't realistic to think that Bryan actually would have won in this instance.
In Brock Lesnar getting the nod to end The Undertaker's undefeated streak at WrestleMania 30, it was clear WWE was awarding him a unique push and readying him for a WWE Championship reign. In all likelihood, he would have squashed Bryan rather than John Cena at SummerSlam 2014 had Bryan been medically cleared. It's unlikely that WWE would totally change directions with Bryan challenging Lesnar at Levi's Stadium.
The story of Lesnar vs. Bryan likely as not would have been that of a competitive match, with Bryan holding his own, but ultimately succumbing to the overwhelming force of The Beast Incarnate. The outing wouldn't bury Bryan, but neither would it derail Lesnar's run on top.