They'd have to create a bunch of new people, because it doesn't really make sense to have people that already have powers, then also give them GL rings.
So plenty of people have lots of willpower in Marvel. But if the Corps actually came to Marvel, we'd just be seeing a lot of no-names popping up with rings.
....maybe something for all those de-powered mutants to do. 😂
Marvel has plenty of Cosmic Gaurdians as is. They really just are more creative in thier characters. Every one in DC is a Superman person, batman person, flash, or green lantern. In Marvel you have the heralds, the nova corps, the elders of the universe, the eternals, the inhumans, the asgardians, the shiar imperial guard,the infinity watch and others i'm prolly missing. at one point there was the star masters as well. it's lost of people already out that do the job of the gl's. they just happen to be more varied.