I ended up fixing mine by "editing" my imported-Wii-Mii - each feature one at a time. For example, I went to the eyes, then hit each edit button in the left-hand column until was set all the way - counting as I went. Then, I'd edit my new Mii by setting the left-hand column all the way, then tapping the right-hand column the exact number of times equal to the number from the Wii-Mii. I was able to replicate my original Mii exactly - it took a while though...