Who's the most invincible and least likely to be dethroned?
And who's most likely to drop their title first out of all the champions in the ufc?
UFC Title holders
demetrious johnson
dominick cruz
Jose aldo
Ronda rousey
Ben Henderson
GSP
Anderson silva
JBJ
Cain Velasquez
my picks are:
Most invincible-JBJ (can't see him losing at lhw to anybody, his only legit threats to face are Gustafson,mousasi and Cormier if he cuts weight)
Most vulnerable-Dominick Cruz (Been out out with injury for so long and then having to face a killer like renan barao when he returns, I have to say he most likely if this fight happens this year) 
I agree that JBJ is by far the toughest one to beat. I don't think Gustafsson, Mousasi, or Cormier stand a chance either. I think Johnson is the most beatable though. He's agruably lost a couple of close decisions recently and probably would have been finished by Uncle Creepy if he hadn't have tried to show boat.
JBJ in the strongest position hampion wise imo.. and id have to say cruz would be most likely to be de throned bexause of the HUGE lay off and a bad ass interim champ.. 