ED/SD are effectively the same. 480 lines whether progressive or interlaced is terrible.
And having the WiiU upscale it is unlikely to make the picture look any better unless you've got a really crappy tv. All high def TVs automatically upscale SD (or ED) signals.
Play your "definitive" Geometry Wars on your wii then try it on the wiiU, then come back and tell me how much better it looks. (Gawd but I'd piss meself if it does look better on your telly. But I'm guessing you've got something with a half-decent upscaler in it, so it won't.)
Actually you're usually better off letting your console doing the upscaling. A console GPU, even one as old and outdated Radeon HD 2000 that you've got in the 360, will do a better job upscaling than the vast majority of tellies. Unless you buy a big name top of the range telly you're going to get a comparatively shite upscaler inside the box. Even mid range big name brands have shite upscalers compared to the 360.
And all my Wii games are copies so it won't be going anywhere near my U lol. I'm thinking of buying the Metroid Prime Trilogy and Xenoblade Chronicles so that I can play them in 1080p. The environments in the latter look impressive in 480p so I can't wait to see what it looks like upscaled.
Have been playing Nano Assault Neo again, it really does look stunning. Weird that third party developers have beaten the Nintendo studios so far with regards to showcasing next gen quality graphics (Trine 2 and Nano Assault Neo), lighting (ZombiU) and GamePad usage (ZombiU and Trine 2). We'll probably see something more impressive looking from Nintendo at E3 next year I guess.