Yeah, Bj would murder Aoki. I want to see Edgar vs Bj, personally. Gray is a boring fighter, and his stand up is really bad... Edgar has really crisp boxing, good footwork, good head movement, and good wrestling as well.
If Bj took Edgar down, though, it'd be over pretty quick I imagine.
Not only do I see Maynard as a better fit opponent to challenge BJ but he also holds a victory over Edgar. For this reason alone I think Gray should be next in line if he gets past Nate.
Do I think he could beat BJ? At this point, probably not...but Penn will have to defend the belt eventually so opponents will be needed.