I really personally hate the way that Gracie fights. I can always appreciate some good Jiu-jitsu but Renzo is not active on the ground.
It always looks like he doesn't even go for a finish. Appearing more so as if he's looking to equilize his opponents activity and is comfortable to lay on top and squeek out a victory in a side mount.
With that said, his take downs are always fluent, and I see him dry humping a victory out of Cung. And holding the belt until he encounters a real BJJ fighter. Or even a fast striker that'll KO him when he shoots.
I don't think you're going to find a much faster striker than Cung Le. Maybe if Denis Kang or Akiyama came over (I don't know if the EliteXC is as exclusive with their fighter's contracts as the UFC) then he might face someone a little more well-rounded with solid stand-up... but out of the EliteXC, Cung is top dog.
If Renzo would learn to GnP in conjunction with his sub attempts, he'd be a lot more dangerous. But we just haven't seen that out of him. I personally think Renzo should have retired, but maybe the fight with Cung is just the catalyst to push him in that direction.