I'd laugh my ass off if the death curse happened. ("Good work, Acererak!")
I thought the same thing Burnside. There might be a whole contingent of people (factions?) that may not want to Curse to end. Perhaps this could be a whole new nemesis of encounters in the jungle: people trying to stop adventurers from succeeding.
Myself, I've also framed the adventure in my own unique way:
If I understand the basic plot correctly: Acererak wants the atropal to feed/store enough souls in the Soulmonger so that it can become an evil ‘death god’. That ‘death god’ would kill everyone so that only undead creatures would be left inhabiting the world.
Using this premise, and that Acererak gets amusement from the suffering/death of adventurers to his traps, then why would he keep his tomb a secret?
I propose the following:
As in the original adventure, when the first signs of the Death Curse were discovered around the world, many divinations and auguries were cast to determine its cause. In addition to discovering that the source of the curse is in Chult, these divinations also specifically point to the city of Umu. Not only that, but Acererak personally took credit for it (a brazen calling card).
This would taunt many would-be adventurers to Chult…and probably to their deaths (which is what Acererak wants). And the most powerful adventurers (Elminster, Drizzt, etc) are probably all suffering from the curse (having died at least once in their careers) and now too weakened to hunt down Acererak (or just fear permanent death).
Instead of a trickle of adventurers trying to uncover the mysterious clues in a sandbox crawl to Umu, this would be more akin to a ‘gold-rush’ of would-be heroes all flooding into Port Nyanzaru, each jockeying to hire guides and porters, so they can be the first to ‘save the world’ from Acererak and his curse.