First, you need a writer/director who understands that Robert E. Howard's Conan isn't fantasy the way that Sindbad is fantasy. In fact it's barely fantasy at all, but rather closer to historical fiction with fantastic trappings. Robert E. Howard was all about realism, even with the magic and the monsters, and some Conan tales have very little fantasy element to them at all. So first, the film needs to look real. It needs to look like HBO's Rome or Ridley Scott's Gladiator. (Not actually Rome of course, but that level of realism.)You guys know I love Hercules and Xena but that isn't what Conan needs to look like. Think of the old Batman Franchise where Gotham City looked like a Star Wars set, and the new one, which takes place in the real world. A Conan film needs to be thought of as taking place in the real world. Maybe given a Mesopotamian look. (Though that would change depending on what story you were adapting. Howard used different pseudo-historical settings.)
Second, adapt one of the Robert E. Howard stories. Don't make some pastiche pulled from six of them or worse just graft the Conan character onto a throwaway wish-I was-directing-Pirates-of-the-Caribbean summer movie plot. I've heard filmmakers saying the REH stories aren't filmable, but they used to say that about the Lord of the Rings. It just took the right writers and director. Red Nails or People of the Black Circle both have enough story to generate a two hour movie and Red Nails in particular has a cast that would hit most of the idiotic Hollywood demographics without any additions. You know, strong woman, slinky woman, stalwart friend, burly villain, creepy villain, etc. All right there on the printed page.
Finally, not to invoke Peter Jackson again, but you need someone who likes and appreciates the source material as Jackson did with LotR. Now, what do I think the odds are of ever getting all this? Not too good. But as Mikey Boy says, there's still hope.