People are already doing that with sub stats anyway despite how inconsequential it is to your gameplay. At least with different stats, you can feel some form of empowerment from gear. Also balancing nightmare, it's not like the developers are that incompetent to make something astoundingly op compared to everything else that's available.
Plus people are excluding people from groups for the silliest reasons in the first place, having different substats wouldn't be anything new in that regard.
