I'm generally against Bans and Restrictions in any eternal format, this one is no exception. Mentor has been the most exciting and fun card Vintage has ever seen and now it's restricted. They've been hacking away at shops for years now, one day the tower will fall and shops will go from dominant to unplayable, maybe we are finally here. Personally I think shops is an important part of the Vintage meta and think it's tragic that they continue to pull it apart.
I don't care if a deck or card is dominant, to me that's what new cards are for, like Mentor was. Vintage is supposed to be broken and I'm sick of these bans. Grumble grumble grumble.