Killer Instinct was released on time for the ONE's launch. However, you only get a few characters as of now and will have to pay for more characters throughout the following year. What makes this reasonable is they sold it initially for 20$ and have each character up for purchase for a certain amount of money... I think.
What if Nintendo did this with Mario Kart 8 and Smash Bros.? If Wii U doesn't match last holiday season's sale, I think Nintendo should try to release these games as fast as possible without compromising the quality of the game. I think the Killer Instinct model is the perfect method to achieve both goals.
They can even make a better selling model. What if they sold the game incomplete for 60 each but guaranteed all unlockable content (that would have been in the game if released later) would be downloaded for free? For insurance, gamers who buy these game will also get a 60$ eshop card which they can use. However, if they use the eshop insurance, the games will be deleted (but not save data) and they can't download the game again until its finished.