#1 Brock Lesnar vs Roman Reigns
This match looks set to be the main event next year at WrestleMania. So, instead of discussing how uninteresting the feud will be (much like the Lesnar vs Goldberg III match last year, where everyone knew the outcome) let's see how WWE can save the outcome from being booed and make the match interesting.
Firstly, The Shield must not break up. Roman should ask his partners not to get involved in the match as he wants to win it by himself. However, The Shield should anyway interfere in the match and then when everyone would expect them to turn on Reigns, they could attack Lesnar and triple team him to help The Big Dog to win.
Reigns turning heel in the WrestleMania Main event will definitely be something no one would see coming.
This way the WWE can protect Lesnar, in case he decides to renew his contract. You give the WWE Universe what they want, you get what you want, and everybody wins in the end. And that will be Best for Business!