Well, it's now getting a Super Mario themed mash up pack, so that's something. And we've got pages for SSX on Tour, Skylanders and NBA Street V3 due to their Mario crossover content.
My gut response is that this is more among the lines of things like Tekken Tag 2 and Bayonetta 2, where Mario-related skins and modes are added to an existing game, rather than an actual crossover.
The press release does say the content pack has "a new area" so depending on how substantial that is, my opinion could change.
I'd lean towards a guest appearance, like SSX on Tour or NBA Street V3. It's an officially licensed graphical overhaul, with nearly (if not literally) every single item swapping skins to fit the Mario theme. The theme doesn't impact the game, as far as I can tell, but if it basically looks like a Mario game with a more blocky nature than usual, I don't seem the harm in writing an article for it.
I realized after writing my post my stance might seem inconsistent because we have pages like StreetPass Mii Plaza that have Mario-themed costumes and items but tbh, I think those should go.
Other than skins and graphical textures, there is a Super Mario themed world.
There are a number of Mario references in this world (according to the map), like:
- the whole SMW world map at the bottom right corner
- Isle Delfino at the top right corner
and also:
- Peach's Castle from SM64
- Acorn Plains from NSMBU
- Bowser Lake from SMW
- Various statues (like Mario, Yoshi, Peach, etc)
- Sprite art
- World 8 as the Nether world
The whole world itself is designed to resemble a world map.
EDIT: This list is incomplete. This means there's more to this world.
These Mario references would overhaul the 'Reference' page. I think we should create a page with character skins, texture replacements, and information about the Mario-themed world. Maybe name the article either 'Minecraft: Wii U Edition' or just 'Super Mario Mash-Up Pack'.