I don't think anyone at MW currently can beat Weidman other than Anderson. I mean Vitor has the power to end it, but off TRT I give him no chance. He isn't elusive enough to stay away from TDs. Mousasi is good, but has no wrestling and would have to sub from bottom somehow. Jacare may be a good fight.
I give Jacare the best shot other than Anderson. I do think if Machida moved down and did well with cutting weight that he would beat Weidman. He could be boring and out cardio/out point Chris.
I hope your not basing your comment on Mousasi's wrestling by the last 2 fights he's had. His fight against Mo Lawal was an aberration, he was far too relaxed and by the time he realized Mo had humped him to a decision the fight was over. I liken that fight to the GSP/Serra fight, GSP went into that fight thinking it would be a breeze (which it should have)and all of sudden he was one and done. Mousasi looked like he had Octagon jitters in his last fight which I'm sure he thought wouldn't happen considering all the places he's fought. No one is immune to 1st time Octagon jitters, unless they're too stupid to know they should be nervous. I think Gegard will have the same kind of success he had in Pride.