No heel been has built up well enough to seem credible. I'd have him go through some midcarders, take on Triple H at Mania, then maybe Rollins will be about ready to return and they could have a long back and forth feud.
Lesnar is pretty much over wrestling. I could hear it when he was on Austin's Podcast. He wants to hunt, farm, drive around in his pick up truck, and be with his family. He's gonna do the minimum to get paid. So, it's gonna be hard to get him involved in anything but an attraction match.