Would an 'Allow deprecated cards' option on automatch be possible? Not with the intention of deliberately matching against another player with the same setting, but merely to allow deprecated cards to be part of the selection for the Kingdom if both the players have set the option.
Technically possible, sure. But I don't think you're going to convince Donald or me that it's a good idea. (Convincing me is kind of irrelevant, you'd have to convince Donald, but I just happen to agree with him on this).
Those cards got removed for a very good reason, and the game with their replacements is just better imo.