Are you serious? Being Asian, Russian or Black doesn't make you 'xenos'. The Imperium isn't racist there are whole chapters representing different ethnic backgrounds. There's no need for it.
I'd agree with Waffles actually, mixing stories from two completely different sci-fi universes is never going to work. The Star Trek races would not be the way they are if they lived in the 40k universe. In the same way having the Star Trek show trying to shoe horn berserkers and nids in just wouldn't work. The crew are hardly going to beam down to a world of frothing monsters each week.
agree with you on that there is no real need for it, being a gay woman myself i suppose i might get hung drawn and quartered but i would like to think that the 41m has its own problems then petty rascism or the like. i can see the fact the two universes wouldn't work really but it might be a giggle in some way shape or form