You're approached by a Hollywood exec...

[Ralif Redhammer]

The big one is the “White Saviour” thing. They could cast someone who isn’t white?

Yeah, as @billd91 pointed out, even doing that is fraught. It might be possible to pull it off, but there are so many landmines inherent in the character. As influential as Tarzan is, his time may have passed.

Remake At the Earth’s Core instead.

I'd be down with another go at adapting Pellucidar. If I recall correctly, it would be less fraught to adapt than Tarzan.

 

[Bohandas]

The biggest issue with this kind of thing is that I don't know enough to give a sensible answer. I know that historically the biggest source of top quality movies in the past was the mid budget movie or even the better budgeted B Movies, not the deliberate attempts at blockbuster movies.
I do not know enough about the movie industry financials to really tell where that money has gone but I suspect it hangs around in streaming services these days.
As for what material might be the source of the "next big thing", I feel if I have heard about it, then that is not it.

I don't see that as being the question for this thread. As far as I can understand this thread is asking what you want to see made.

 

[OB1]

I'm gonna go in a bit of a different direction and say the Anita Blake Vampire Hunter series by Laurell K Hamilton. Think True Blood meets Bosch with a female lead, well over 20 books to pull the series from, and an overarching plot line that keeps getting weirder and more gonzo. Not to mention that sex and violence sell great on HBO.

 

[Clint_L]

I would love to see Becky Chambers' Wayfarer trilogy turned into a prestige series.

 

[Pale Violet Light]

Bakker’s Second Apocalypse, animated, late night on Adult Swim (if such a thing still exists) along with all the dodgy anime. It will attract an audience of dozens, at least.