Skitarii is probs the one that is the most plausible, but man I wish we could get some Xenos.
I realized this with the latest trailer, where I thought how insanely cool it is to finally actually have a proper 1st person 40k game and just see shit like a combat shotgun being shot and reloaded etc in that setting. Like that's weirdly a first.
But then I did get a bit disappointed because the setting/theme of the game restricts it to human stuff. Imagine you were instead some rogue trader's posse featuring a human ofc, Eldar, a fire warrior, and maybe Ork. Getting to use all 3 of those xenos' weapons in like a proper 1st person game would be so cool. (no the fire warrior game doesnt count)