nintendo was able to save the 3ds from a vita-like fate, and they managed to turn the ds around, but the ds in particular had a vision behind it supported by some very unique and easy to understand software. it didn't hurt that the ds lite basically served as a launch for the ds as we know it- i don't know if nintendo will be able to slim down the wii u in the future.
The bad thing about Nintendo is that their visions clearly are on a project/game/problem basis so far. I'm sure they strike gold with some games again, but the importance of a coherent overarching vision for a system that needs to be continually nurtured still doesn't seem familiar to them. Maybe next gen then.