There was a rumor last night a few hours before RAW there was a meeting. It is said during this meeting Vince McMahon if offering Brock Lesnar the largest contract he has ever offer anyone. This has said to have upset a lot of people backstage and many believe Lesnar just isn't worth it. However if Brock doesn't resign, Vince McMahon will make sure Reigns will go over on Brock in the biggest way.
If Brock does resign, it is rumor that The Rock will somehow play a role in the Reigns vs Brock match and it will plant the seeds for Brock vs Rock for WM 32.

There is no way in hell Brock signed for "the largest contract in history" when Cena makes $5M downside. Maybe the largest per date or whatever, but there is literally no chance IN HELL Cena will make less money.

Also, absolutely. Brock vs Rock absolutely will happen at WM32 if Brock is re-signed.

He just isn't worth this, if it's true...

I can see the Brock Lesnar screwjob being a thing.

if the Lesnar screwjob is a thing, it's because of what happened at Mania 20.