I don't find the new traits to be the best control for Hero specs. It is somewhat of a pain in the butt to lose the trait slot, but it is massively overshadowed by the power of the hero specs. Also, I'm probably taking Savant anyway on any psi character! :) I play with selected Origins, by the way.

I'm not even sure if this is possible, but I think a much more meaningful restriction would be to only allow one soldier with a hero spec on any given mission. Not sure if that should include faction heroes, but probably not. I think that would still let players have their RPGO hero characters, restrict their impact, and even act like a singular avatar for the player on any mission where they include a hero in the squad.