#1 Brock Lesnar successfully defends the Universal title

No one would want Brock Lesnar to win the Universal title at WrestleMania 35. The Beast Incarnate has held the title hostage for quite a long time now. People see Seth Rollins as a savior who would probably slay the Beast.
However, the Kingslayer may not turn out to be the Beast Slayer. This is due to the fact that Seth Rollins was not Vince McMahon's original choice to face Lesnar at WrestleMania 35. Triple H apparently recommended him.
Did Goldberg ruin Bray Wyatt's career? - Watch Now!
Also, have in mind that this match is not going to main event WrestleMania due to the popularity of the women's title match. Vince may not like the idea of Brock getting pinned out of nowhere, that too in a match other than the main event.
The Beast may hold the title hostage even after WrestleMania, but it would not be a popular decision. The WWE Universe is already tired of Brock Lesnar's title reign. His reign extending beyond WrestleMania would certainly push the fan outrage to its limits.
WWE will have no problems in handling fan backlash, but what they do with the part-timer as their champion after yet another WrestleMania is anyone's guess.
One wrong move ended Big E's career - Watch Here!