Either way I would of held onto the Wii, as I agree its a lot easier using that for my GCN games. The fact that the games do look better / less HDTV lag by using the Wii U is swaying my decision if I want to transfer the files over or not. The 16:9 automatic stretch factor doesn't bother me, as the annoying black side bars are the greater evil, personally.
Even though I consider the Wii U to be a superior option for playing Wii titles, I'm still going to hang onto my Wii, and I'm not going to use the transfer function. I hadn't over-invested in either Virtual console games, or save data for my original Wii. I'm fine with starting fresh for most Wii games on my Wii U.
I also still feel that the original Wii is one of the best methods for playing GameCube games. This is partially due to the Wii's superior 480p support, and the broad availability of component cables for the Wii. The only component cables for the GameCube were first-party, and are extremely rare. (and only work for earlier versions of the console)
I've mentioned before that I'm a collector, though. So it's not really surprising that I would hang onto old hardware.
I won't be getting a Wii U anytime soon though (too much Wii backlog as it is), so this is all just future thinking.