#1 Have Brock Lesnar threaten to walk out with the Title
If WWE is really intent on making Brock Lesnar the villain here, which seems to be the case with Roman Reigns's scathing promo on The Beast Incarnate on Raw, there is no better way to do that, than to have him threaten to walk out on the company with their biggest prize around his waist.
Not only would this put Roman Reigns in the position of being the protector of the WWE, it also allows for WWE to blend storyline and reality in the best way. Of course this might seem like a copy of the storyline that WWE did with CM Punk during the 'Summer of Punk', but Lesnar's rumoured departure for UFC creates an interesting wrinkle to the whole thing this time around.
In the end, WWE needs ways to make this match more appealing to a very fickle WWE Universe. Creating a situation where there are possible long lasting effects if Brock Lesnar were to win, could be the best way to do that. It might even be enough to get fans behind Reigns in a way that they never have before, especially if the future of WWE rests in his hands.