He made a deal with our pal Bwonsamdi to serve him in Life and in Death. But what would that entail him? Is he doing his taxes he gets from other people he makes deals with? Or, is he walking around one of the many temples in De Other Side, and serving past Zandalari royalty food and drink? He promised to serve him, after all 
Would be interesting to visit De Other Side un-instaced/in the future and see how he’s doing in game
(This is mostly light hearted fluff, btw)
He is resting.
Instead you’ll meet 2 gnomes. Enjoy the other side.
It would be interesting if Rastakhan’s spirit was elevated and became to Bwonsamdi what Bwonsamdi was to Mueh’zala, but I imagine two trolls ascending to godhood at once would be a bit much.
Knowing Bwonsamdi I imagine he has Rastakhan wandering the Shadowlands going house to house and trying to convince various death entities that they should totally sign up for a deal with Bwonsamdi to clean up all their nasty soul-related problems. Sign up now and you’ll get a portable vacuum cleaner and an electric razor absolutely free!
Not Really, i mean, we have many powerfull Characters at this point, maybe it would be a little bit more even, if we got two powerfull Trolls at once 
in my eyes, unfortunately, has Rastakhan really to serve Bwonsamdi and maybe even a cruel destiniy for the first time, to humble him.
Unclogging the soul hole.
You know, I was kinda thinking a while ago how they’d bring him back if they had the option to. Just look at how Vol’jin end up. He’s going to be a Loa now 
Rastakhan becoming a Loa could be one of said ways to bring him back, because I could totally see him being a Loa of Light and the sun. Or, Bwonsamdi could just ressurect him, and he’d just come back as a zombie, albeit an intelligent one. Hell, Dazar could become a loa too. As the first Zandalarian king, I think this would definitely be a good role for him he could be a Loa the protects all of Zandalar, and the races who live there, be they trolls, Vulpera or even Sethrak. Any Horde who’d be on the island would be protected too, I’d say. The Zandalari could call him the Sun/Light King, and say his spirits lives on in all Zandalarian royalty. But, I think Rastakhan is more deserving due to his very short life in BfA. Just my opinion though, I think having three ascended trolls would be cool
Floating around?
I will usually gladly hop on the Rastakahn QQ train, with its various complaints:
He was built up for near decades, and was killed off almost instantly after being placed In Game, to make way for a blank slate of a neophyte in his daughter.
The Horde didn’t even officially have him, as the Zandalari joined under Talanji’s reign. So the Horde can never really claim him as one of theirs, or claim his loss. The most we could say is Rastakhan was nice to us and welcomed the Horde into Zandalar.
But having said all that… I hope he is done. That he is just preparing a place for his daughter - in the sweetest way. Maybe he has one or two conversations. Maybe a flashback or two. But I feel like he is done for. Let him be a task master of lesser Trolls, keeping the Other Side in good shape and tidy for his daughter and future grand kids.
Rezan is being removed and leaving a portion of his power to Voljin, who may be returning. I would rather have that be the focus.
Although… if Death Knights are freed from Bolvar and Arthas… and other Death Entities get their own brands of Death Knights… having Rastakhan be Bwonsamdi’s Death Knight and the Horde’s Zandalari Death Knight NPC could be neat.
Omg god imagine. Rastakhan becoming the loa of death under Bwonsamdi and take the appearance of a dead t-rex!!!
Resting and enjoying a vacation as we saw him conforting briefly her daughter at the end of the recent book.
That said I do hope he plays an Obi-Wan role appearing to give advise to Talanji in ruling while Vol’jin fight outside enemies(founding and foiling schemes feom bloodthirsty gods like the future jailors)
Smoking mojo and tapping troll cheeks.
Concerning the situation, potentially in que with the other trolls as Bwonsamdi is attempting to hold all the troll souls away from the maw.
Technically, you aren’t in the Other Side when you meet those gnomes. But… yeah, Milhouse and Millificent Manastorm aren’t what I expected. I figured it’d be, like… Jin’do being Hakkar’s tortured puppet, Zalazane, or perhaps even mighty Zul’jin.
Nah, gnomes.
I’m sure he’s making friends on De Other Side:
Man I wish that was one of the deals, we save Jin’do from Hakkar and we put him asleep to figure out if he’s corrupted or a form to turn it at benefit of everyone
Also, it would be sweet if one of the bosses were either the first windrunner general that is trying to escape and Zul’jin helps us to put it down again.
I mean let’s be honest here. Blizz took a look at Shadowlands and realized not a single gnome exists in it anywhere in the entire expansion, so they panicked and threw these two into an open boss slot they had in De Other Side and called it a day.
Yes!! Ive seen this pop up from a few people now. Rastakhan ended up being one of the best new characters in the horde experience, even with how hard of a smear campaign mop ran against him. I think it would be great to officially add him to the horde roster and with him being an avatar of a powerful death entity horde will funnily have a powerhouse to fight for them. They could have him rival any of the alliance demigods.
It was still a cute conclusion for the two. 
I honestly would rather have some awesome encounter werewe fight the invading force that tries to break to the other side, and where we’re assited by Rastakhan, Sen’Jin and Zul’Jin to defeat the foe.
And to show some fun mechanic/ theme. Like a place where people are partying and having fun and then you see Jailer’s minions coming in and you go to defent the souls that are attacked, and in return they come backon final boss encounter to defend the Other side.
Nah, that’s probably just Bwonsamdi on a daily/nightly basis. I could see him doing that though
Bwonsamdi Death Knights! They should’ve been playable from the start of BfA, but with a special introduction 