Since I've only JUST BARELY beaten the FIRST adventure map for the Wii U version, I can't even begin to imagine what these additional maps would do to my playtime. It's a shame that they aren't coming to the Wii U version, but then again, you have to sell units with exclusivity in mind.
Does Legends have all the DLC maps from the original game? If so, I feel truly screwed. The Wii U version will just forever be the inferior one, since it lacks the Legends Adventure maps, and Nintendo is pretty much asking me to shell out half the price for the Wii U version plus DLC.