#3. Not as good as Roman Reigns' current run: Brock Lesnar (2017-2018)
Brock Lesnar and Roman Reigns have crossed paths numerous times in the past. The first time it happened was in 2015 when the main event of WrestleMania 31 was between Brock Lesnar and Roman Reigns.
The second time was three years later at WrestleMania 34. Even before WrestleMania 33 in 2017, it was rumored that the following year's main event would be a rematch between Roman Reigns and Brock Lesnar.
That year at WrestleMania 33, Brock Lesnar finally defeated Goldberg to win the Universal Championship, while Roman Reigns defeated The Undertaker in the main event. It would kickstart Brock Lesnar's lengthy run as the Universal Champion while WWE tried to build Roman Reigns once more to get his coronation.
Brock Lesnar was as dominant and legitimate as a World Champion can get, but his lack of appearances caused a problem. It was only once every few months that fans got to see Brock Lesnar defend the Universal title, though he did have some incredible matches in that tenure.
Perhaps the two most memorable matches in that run were his Fatal-4-Way title defense at SummerSlam and his Champion vs Champion match against AJ Styles. Shockingly, Brock Lesnar defeated Roman Reigns in the main event of WrestleMania 34 in what fans thought would be a guaranteed coronation.
Instead, they crossed paths again in Saudi Arabia and met later at SummerSlam 2018 - where Roman Reigns finally defeated Lesnar to end his 503-day Universal title reign.
Brock Lesnar's title reign could have been greater, but it felt longer than it needed to. The lack of title defenses makes Roman Reigns' current run far superior.