Say what you will about the gameplay in Draenor... but personally I still enjoyed the world, music, story, and characters a lot.
Recently I was flying around Draenor finishing up some reputations to get mounts and I was reminded of the fact that destruction was still for the most part averted on Draenor. Shattrath and Karabor are standing and both the Draenei and Orcish armies of Draenor are still likely a force to be reckoned with.
In the ending cinematic for WoD after Archimonde is defeated we see this exchange between Y'rel and Khadgar:
Y'rel: "You... you don't think it's over?"
Khadgar: "Gul'Dan, and the devils that command him... are not so easily banished. I fear this is only beginning."
Y'rel: "If you ever need us, we will be here."
Khadgar: "Until we meet again."
Now we are approaching Patch 7.3 and taking the fight to the Legion's homeworld of Argus and it made me start thinking - Will we see some of Draenor's forces aiding us in this campaign against the Legion? Or even perhaps just a small cameo?
In general I think it would be really cool to see a lot of different factions we've fought with throughout the history of Warcraft all present for the fight on Argus. I remember one complaint with Arthas in Wrath of the Lich King is that we didn't get to see enough characters have their closure with him.
I hope we get to see a diverse army in the Patch 7.3 'campaign', even if they can't make an appearance in the raid itself or have major moments in the story. So many factions and characters have a big reason to want to be part of finishing off the Legion.