Can’t say I’m surprised that Islam is the favorite in that matchup. Obviously the size makes a difference, but it’s not the only factor. Islam is arguably the best grappler in the UFC at the moment and if I’m perfectly honest I think his stand up game is very underrated. Personally I thought Oliveira would have a clear advantage on the feet, seeing how he was able to hang with some very good strikers, but Islam proved me wrong.
So far no one has figured out a way on how to beat Islam, other than the guy who KO'ed him early in his UFC career, but that loss doesn’t matter these days anymore.
I rate Volkanovski very highly and I’m not saying he has no chance at all, but I think a victory for him is unlikely.
I honestly would have preferred to see Islam vs Dariush next, as I think Dariush has earned it the most, but it is what it is.