Well, it is a Wii Sports game on Wii U, but it should have been much different. They didn't add nearly enough content. Instead, they took the original Wii Sports, added motion controls, added HD, upgraded to graphics a bit, and added online play.
No, it wouldn't.
How do Mii's look different in HD? Wii sports strength was its simplisity, not its 'vast' content.
The current additions were the only things which could be added to the Wii sports franchise. Nintendo cannot take it any further that this. It makes full use of the hardware and controllers. Nothing else to try out.
The only thing they could add now is some free and more specialised modes - which will come later when Nintendo is adding up the sports. But that's keeping the existing customers happy, and not really selling it in the first place.
In the wilderness we go alone with our new knowledge and strength.