Frankly, I see a better benefit out of this. If Nintendo can do this and add Wii functionality to old gamecube games, they should use it for their own research and development.
Think about. They could add wii functionality to Mario Kart Double Dash. Then, they could test out the game and see what types of tracks work and what don't. They can then fiddle with ways to control. All of this research can then go into the next Mario Kart built specifically for Wii and will mean they can make a Mario Kart game that is absolutly perfect for the Wii.
Frankly, that's what they should be doing. Putting Wii in existing games and testing to know what's going to work for the future, thereby saving time of having to create whole new games from scratch and tinkering and experimenting with controls while many parts of the game or vision are missing or incomplete.
As for selling the old games with new controls, I'm not for it. I have not bought the Game Boy Advance ports of old Nes and Snes games. I just don't the need. I own all these games and there's been talk of being able to load old Nes and Snes games to a person's DS besides just being available on the virtual console. So, I'd rather wait and see. The same is with the Gamecube games. Some of these games I've put long hours into, like Rogue Squadron, F-Zero and Mario Kart. Wii functionality would be nice, but after having played the game for so long before, I'm not going to play it that much. I want something new.
If you want budget titles, that's what you can use the old gamecube games for. The system is backwards compatible. I've never owned a Gameboy Advance. But I have 5 GBA games now. That's because I bought a DS and thanks to Backwards functionality, I bought some games that I was interested in but never enough to buy a Gameboy Advance. I think the same thing could hgappen wioth Gamecube games. If a lot of people didn't own a Gamecube but were interested in some old Gamecube titles, chances are, if they buy a Wii, they'll take advantage of the backwards functionality.
If they do add Wii functionality to old games then I suggest one of the following:
a) They sell games in a compliation, like 4 or 5 games on one disc
b) they package the game with it's new original Wii counterpart, thereby giving extra value to the purchase.
c) they use it as a promotional item
Frankly, the best choice to me is b. It also has the added benefit of keeping people from ruining the joy and pleasure of experiencing the new control scheme in a game. If I played Mario Kart Double Dash with the Wii controls, what would be the thrill in playing the actual Wii Mario Kart? Sure, there'd be new courses and characters and most likely internet play. But playing it with the remote will have already been experienced.
This is why games like Mario 64 and Zelda: OoT were big. Games like Banjo-Kazooie, Donkey Kong 64, StarFox 64, Mario Kart 64 and Mario Golf were big. It was the first time these characters were in 3-D and their universes could be explored in 3-d. You were able to control them in these worlds with the analog stick for the first time. And it was a new gameplay you were experiencing for the first time. Metroid Prime was bigger than Metroid Prime 2. Why? First time experiencing Metroid in 3D. While there are other factors that can be argued, the truth is, the first time you play something with a new control scheme, it leaves a much larger impression than playing a second game with the same scheme.
That's my warning.