Brock Lesnar doesn't HAVE to hold the WWE WHC for a long time

Well, for months now, I've heard people saying that Brock Lesnar will win the WWE World Heavyweight Championship at SummerSlam, and how impractical it might seem considering how few dates he will work. Everyone also seems convinced that it will be Lesnar passing the torch to Reigns at WrestleMania 31. But is it all set in stone? Of course not. Plans may change, as well they should. I agree that Lesnar holding the title for roughly 8-9 months while only showing up once in a blue moon would not be a good thing. So, who says that he can't drop it to someone else? Hold the title for a few months, drop it, then win it again in time for WrestleMania, if that's what WWE truly wants. I don't know WHO he could drop it to. Maybe you guys have some ideas? All I'm saying is it seems like that might be the best thing WWE could do. What are your thoughts?