#2 WWE may be seeking a shake-up of the order with Brock Lesnar and Roman Reigns
World champion versus world champion is something WWE does only when something big is in the works. In this case, neither champion can afford to lose, especially because this is pretty much the apex of stakes as far as WWE is concerned.
Whoever takes the win between Brock Lesnar and Roman Reigns will receive a major boost in credibility. As a double champion, that person will be the centerpiece of WWE, and any storylines from then on will have to involve him defending both championships.
It could also result in WWE having the champion keep one title and drop the other to a rising star to elevate them. This would ensure fresh faces and new champions and keep the product engaging.
#1 Brock Lesnar vs. Roman Reigns is an explosive and unpredictable main event
Brock Lesnar and Roman Reigns may be contesting the biggest WrestleMania main event in many years. WWE have a gold mine on their hands with these two superstars, and setting them on a collision course at Mania is what's best for business and for the fans.
More importantly, however, it is the first main event in many years where predicting the winner isn't a piece of cake. One can make a case for both Lesnar and Reigns to walk out of WrestleMania with both titles on their shoulders. WWE have the ultimate battle on their hands, and for once, the excitement is palpable.