I think this isn't a situation where a Wii port would have been easy and it probably would have cost them more money than its worth. It looks like that the dev platform for this was the PC version and comparing that version to the HD consoles almost makes it appear like a next generation game.
Compared to the PC which looks phenomenal and plays butter smooth, the HD twins are stuck with 30 fps (or less), sub 720p resolution, washed out colors, jaggies all over the place so essentially they are already a downgraded ports. The 30 fps really hurts the experience and I really don't think that Sega could have downgraded the game any further for the Wii without a major overhaul to the game.
Funny thing is that I made this exact thread a year and a half ago when I heard Sonic Colors is not coming to Ps360. Luckily then I discovered Dolphin...







