I like the idea, for what it's worth.
I'd say the new requirement should be implemented to every instance where it makes sense. So besides the circlet, there's Tulak's mask, as you said, but also Ragnos' gauntlets. Qel-Droma's robes you can't equip without the Jedi Defense feat anyway. It doesn't make sense to have a special restriction for the robes but not for any of these items. They should've either removed the Jedi restriction thing or applied it to everything pertinent. To be honest, Sith artifacts requiring a Force user sounds way more fitting than restricting non Force sensitives from wearing plain robes.
EDIT: Ajunta's blade is another possibility, though more crippling gameplay wise.