GOT is hot naked sexy people and swords. I feel like Halo isnt that, at all.
Babylon 5 demonstrated that you can keep absolutely everything else crappy (effects, costumes, heck acting and even cinematography), so long as you're good at conversations in rooms.
The Halo universe offers a lot to mine from, just like the Star Wars Universe did for Andor. It's just waiting for the chosen one writer to be allowed to do the job. Who's the J. Michael Straczynski or Tony Gilroy for the Halo universe?