The characters & campaign are great, mostly due to the original creator of the board game, but really only useful for solo players or those with dedicated friends who are willing to pay.
Sadly, the fact that ALL other players also require the DLC, and the fact that you cannot revert a campaign once DLC is added is a huge downside to a cooperative game.
This means that it will mostly only be useful for solo players, to avoid forcing your friends to rebuy something they might never use.
They should honestly considering allowing the new unlocks in co-op if the lobby owner has it, or at least allow their existence in the campaign but restrict access/usage to owners only.