I could see, maybe, the unification of some of the Arab states but that's really about it, and I wouldn't bet that way. Pan-Arab nationalism probably reached its apotheosis with Nasser in the 70's. This is not to say that the next twenty or thirty years will be wine and roses. Yemen is going to look like a vision of hell for one thing.
Having a caliphate was one thing when you had one rich city-state dominating a vast poor expanse. It's a very different story when you have a dozen rich countries, each with their own tiny army, each with their own couple ethnicities, each one wanting to pronounce everything differently and quite unable to agree on who succeeded Mohammed.
It would be really convenient to be able to paint all our troubles with a single brush and a single color of paint, but the truth is much more complex and interesting.
That is so totally wrong I don't even know where to begin. For starters the caliphate was only a political force until the emergence of the seljuk turks. The turkish empire was European focused and never controlled persia or arabia.
They didn't consider it among their more important titles until quite late, preferrimg Qaysar-i-Rum or Emperor of the Romans, but their claim to the Caliphate was long standing.
Personally, I wouldn't want that to happen either.