I don't think that this can work well.
The converter does not know which object belongs where.
At best it could make educated guesses.
But there will allways be cases where it guesses totally wrong.
Just compare it with upconversion in other dimensions (size, colour, time).
It actually works fairly well in many cases though it depends on which TV you have. After all, many 3D movies in the theaters were filmed in 2D and then converted to 3D later, though the process they use requires quite a bit of manual work and is quite expensive. Kind of like the difference between google translate and a good manual translation.
Also keep in mind that if you have access to the game engine it is trivial to convert a 2d game into 3d (check out the psp3d plugin which can convert almost any psp game into 3d for proof) but you would need a way to get that 3D data to your TV. Perhaps the easiest way would be to have a device that plugs into the Wii's USB port and controls the 3D glasses itself. Of course, this would require quite a bit of coding and there might not be enough CPU resources left to do it. Might be easier with gamecube games assuming Devolution works out (though it would probably be limited to red/blue glasses at first).