So, on the Horde side, the desert of Vol’dun has some quest dialog in which the Vulpera make a comment about how the whole area was a jungle and then suddenly it became a desert (which might be the reason why the Faithless went nuts). Later on, you find out that Sethraliss’ death when she fought Mytrax was the reason why the land ‘died’ as her rebirth was being stopped by the Faithless.
Now that Sethraliss has been rescued, will we see a jungle version of Vol’dun? Like in Cata in Mount Hyjal?
Sadly, zones rarely get fixed…just revamped for yet another disaster.
Hyjal was more of a cosmetic change. Vol’dun would be a massive restructuring. Plus it will still take time for a jungle to regrow
Unless they preplanned some event happening in Vol’dun, I hardly doubt it.
Ch-ch-ch-ch-Chia!
Not likely. It would take longer than we will be in Zandalar for it to regrow even with the Loa’s help. And we all know the second the new xpac drops and we move on to where ever it takes us we are never gonna step foot on Zandalar again, let alone Vol’dun.
You can kind of see this vibrant jungle setting present in the coastal parts of Vol’dun which is really a nice contrast from the bleak desert most of Vol’dun is comprised of.
But all of the health nuts on Azeroth are consuming the seeds for fiber and Omega-3s. 
No. Sethraliss is dead. Her rebirth will take a long time.
Torga’s rebirth was sped up because the Tortollans happened to use the scroll of rebirth next to his corpse while it was fresh and his soul was there.
By the time Sethraliss revives and can help replenish Vol’dun, WoW will have run its course.
So what was rescued in the temple? Just an avatar?
It takes time for life to return to any land.
There’s a man in India who’s been converting a resource-stripped desert area into an oasis for the past 30 years on his own.