Somehow, I had one version of my Mii on my Wii, and one version on my 3DS. When configuring my Wii U, I used the 3DS version, since that was the only one I could import on initial setup. After importing Miis and save data from my Wii, I then deleted the duplicate version of my Mii that had been copied from the Wii out of the Wii U's Mii storage.
However, I noticed now that when I boot up Super Mario Galaxy 2 on my Wii U, my save file just shows Mario, not my Mii. Did I accidentally delete my Mii (and thus any Wii Sports save data and any other Wii save data that requires a Mii) from my Wii U's Wii menu as well as from the Wii U's own Mii storage?
Best Answer
Even though they are "duplicate" Miis as far as you are concerned, they are 2 separate Miis as far as the system is concerned.
If you deleted the Mii that was imported from the 3DS, then any content tied to that Mii would be gone. Consequently if you deleted the Mii that was imported from the Wii, then any content tied to that Mii would be gone. Ergo, if you deleted the Mii that was imported from the Wii, then that would cause your Super Mario Galaxy 2 to revert as well as any Wii-specific data.
I tried this by "duplicating" a Mii using my 3DS, original Wii, and Wii U.