I really like your suggestions and I completely agree that he needs to be updated! I like that you changes aren’t drastic but make him more relevant.
One additional change (which is a little more drastic) I’d like to see is a change to his aoe. With the current number of toons that can counter, I find it very difficult to ever really use his aoe, especially since the damage inflicted is almost negligeable. I would like it to not be an aoe. GMY still copies all of the opposing teams buffs, but then maybe cleanses all allies debuffs and heals 20% protection.