There are a huge number of wii's still out there and I believe they are still outselling the wii u. So it probably makes sense for a wii version. To be honest I don't get why wii development has been abandoned by most developers/publishers. There is probably a lot more money to be made with the wii version than wii u currently and of course wii u owners can also purchase the wii version and play with enhanced visual quality.
Exactly. The same applies to the PS2. I don't know why everyone is so surprised and getting bent out of shape because its coming to the Wii and PS2 and not the Wii U. Its a business decision.