I had a thought on this:
- What we fought in The End Time dungeon was not Murozond himself, but a "temporal echo" from an unknown point in the timeline. A diversionary tactic to make us think he'd been beaten. If this was the case, he would've fooled even Nozdormu. This could also mean that Murozond was protected from the diminishing of the Aspects' powers after Deathwing was slain.
- Murozond could also exist concurrently in two different points: at The End Time dungeon, and at his currently-unknown location. With his power split (perhaps by necessity of needing to be in two places at once), that could explain why he was "weak" in the aforementioned dungeon.
I haven't thought out the entirety of a Time-themed expansion with Murozond as the antagonist. Some points though:
- Zovaal wants to rule reality. Murozond wants to destroy it all. He'd rather not exist than face his fate.
- The Infinite Dragonflight would be assaulting many locations across Azeroth, and players would be fighting back ala Legion-style assaults.
- These assaults would not only feature Infinite Dragonflight mobs (with updated models too), but also time-variants of familiar faces.
- The Caverns of Time would be a key location in the expansion, and we may see the Chronal Spire as well.
- In one big patch, we would visit an alternate Azeroth where many things are different. Most noticeable of all is that the super-continent of Kalimdor would be intact.
- When we take the fight to Murozond directly, we may have help from others we have assisted in the past; Outland, AU Draenor, the Shadowlands, and so on. Think of it as "calling in a lot of favours".
- Murozond may have created a predestination paradox; in trying to avert his fate, he will actually cause it. So even though we will win in the end of this would-be expansion, he may escape and try to screw us over in the past, hence our adventure into The End Time dungeon. But we all know how that turns out!
It would be an interesting theme for an expansion, but it would also have to be done right. WoD used time as a theme, but it wasn't well received. On that: if we ever go back to AU Draenor (perhaps to fight Yrel on her home turf in a Shattrath raid?), I'd like to see the sites of the Alliance and Horde garrisons be smoking ruins. Call it a nod to the disdain most of the playerbase had for them.
That sounds cool. Like a Dreamwalker/Sethraliss type fight?