I like playing against the AI in the Revenge campaign because they have all the cards unlocked for their deck, so are more of a challenge.
Is there a way to fight AI opponents with their full decks unlocked outside of the Revenge Campaign?
There is no way to face an AI opponent with a fully unlocked deck outside of singleplayer Revenge Campaign.
If you have another friend who has an unlocked deck, you can start a multiplayer match with them and have them disconnect. This will cause the AI to take over their deck and you can fight the fully unlocked deck when it is AI controlled.