I would love to someday see the Phoenix Sage redone. Especially with the success of Thor and Avengers, it's clear that the movies can easily get away with aliens and more mystical adversaries. As much as I enjoy the first two X-Men movies, I think the series grounded itself a little too much.
Honestly, they could've done Dark Phoenix without needing to go cosmic at all. Instead of eating a star and destroying an inhabited planet, she eats a nuclear power plant and destroys a city. Instead of the Imperial Guard, you use the army, or X-Factor, or Freedom Force or some other government mutant agency to bring her down.
If you should ever watch/re-watch the "Dark Willow" arc of Buffy the Vampire Slayer
, take note of the fact that it is beat for beat essentially an adaptation of Uncanny X-Men
Oh, I get what you're saying, and I do agree that the Phoenix Saga could have worked within these movies without all the cosmic stuff.
I'm just saying that I'd love to see a big-screen version one day that is more true to the comics. I want to see a big flaming bird that eats stars, and I want to see the X-Men battle the Shi'ar on the moon!