Nintendo president Satoru Iwata recently talked HD - a future console would likely support it, but there wouldn't be a Wii-enabled HD.
In an interview with VentureBeat Iwata was quizzed as to whether there would ever be a Wii upgrade to support full High Definition output, or at least hover around the 720 mark (as opposed to the Wii's maximum output of 420p).
The short answer, no, but future Nintendo consoles are pretty much guaranteed the crisper visual modes due to HD-enabled TV sets being near-enough standard these days.
If we have an opportunity to make a new console, it will probably support HD because it is now common throughout the world. However, as far as the Wii is concerned, we have not found a significant reason to make it HD-compatible at this time. What is the significant meaning to users? I don't think we should do it unless we find that reason. If we decide for other reasons to make new hardware, then HD is one of the things we would naturally add.
Should Nintendo have made the Wii HD-enabled to begin with?