#2 Brock Lesnar
Brock Lesnar has been criticized by WWE fans, critics, and even other talents such as Roman Reigns, for being a part-time wrestler. In fact, Lesnar's matches for the entirety of 2018 only barely measure in the double digits.
So, you may ask, why does he deserve to main event Wrestlemania 35? Simple; Brock Lesnar is still far more well known than even the next most popular member of the WWE main roster. Due to his reign as UFC Heavyweight champion, Lesnar has the ability to generate interest outside of pro wrestling fandom, which is crucial to both growing the wrestling business and getting PPV buyrates.
Why he deserves to main event Wrestlemania 35: Besides his aforementioned name recognition on a worldwide scale, Lesnar also has a legit tough guy reputation that lends an air of mystique to his wrestling character.