http://www.computerandvideogames.com/379590/wii-u-upscales-original-wii-games-to-hd/

I'm not entirely sure if that's true, or if it is, to what extent it actually makes a difference.

IGN posted a similar article (with a wayyyy better video) and honestly, aside from more saturated colors, I saw ZERO difference.

http://www.ign.com/videos/2012/11/19/do-wii-games-look-better-on-wii-u

Its strange because it seems the TV is getting a 1080p signal. I know it won't increase rasterization resolution (it will draw in 480) but the Wii U must be upscaling the image before it outputs it

EDIT:

Agreed, I see barely any difference as well

I can't see any reason why it shouldn't.

I saw way, way more jaggies when i was running the Wii U Transfer software (which works entirely in Wii mode) than i did playing Nintendoland, and didn't notice a difference in the Wii U side of the transfer (rendered from Wii U in Wii mode via HDMI) to the Wii side (rendered over Component, 480p)

I'm going to pop in MH3 right now with all this talk.

Wii is more powerful than WiiU confirmed!

It upscales games to 1080p res, but doesn't actually re-render them in that resolution. For that, you'd need an HD remake type of thing.

No.

Think how CoD, for example, is transmitted to your TV as 1080p, but it's actually rendered internally at 600p.

Dolphin re-renders the games it plays.

Have you ever played MH3?  One thing I am noticing is that on the Wii there are the occasional white pixels (artifacts?) that pop up on the background.  I am not noticing them when playing MH3 on the Wii U.  I even went to the area 8 in the flooded forest (a cave) which it would happen a lot on the background of the cave walls and I am not seeing them when playing on the Wii U.  Other than that I don't see any other improvements.  Maybe less jaggies but the missing white artifacts are the only noticeable difference to me.