Yes, I would be ineterested in playing as non-human. After role playing lot of different characters in New Vegas, it occurred to me recently that I want to be a super mutant and go to Jacobstown and live there. And wasteland occupiers react to me differently because I'm a super mutant. Of course this will include dark things like some shops not selling to you because of your species or some factions becoming 'locked out' simply because they don't like super mutants.
I know it's a big ask. But it would be the 'new twist' I would hope for in the next Fallout game (not some crap like settlement building that has no significant tie into the game world).
The idea really is big ask though as skills and perks would probably have to tie into what species you are and I don't want the Obsidian depth gone. I would only say start with two (human or super mutant) so there isn't crazy amounts to tackle and it is some what feasible.
I fear this can only be done if Obsidian were the 'main runners' of the series though (i.e: get 7 years of their own time) instead of piggy backing on what Bethesda does with a spin off title of sorts.