I don't know why Nintendo fans are not keeping their expectations low when it comes to power. This is Nintendo after all. The last time they aimed to have a powerful system, handheld or home console, was in 2001 with the GameCube.
Personally, I think if these rumors are true, you're probably not going to see much of an upgrade from the Wii U, which is still damn good for a handheld. Which also probably does mean a lot of Nintendo games will launch on both. My advice? Just expect Vita graphics and you'll be pleasantly surprised when the NX launches, as it's graphics will definitely be better than that.