Maybe people think that they don't need Wii U to play excellent Mario and DK games, they can do it on Wii, 2/3DS, DS or even older Nntendo home and portable consoles. Classic Nintendo platformers don't need powerful graphics, that if overdone make them look plasticky, cheesy or even uncanny, they are at their best with a cartoony look, and the only benefit they could receive from more powerful GPUs are faster refresh and smoother and better defined edges. Yep, they could benefit also from larger RAM, allowing huge levels, but simple graphics already leave enough room for big ones even with the RAM available in Wii and 3DS, and the typical level structure of platformers allows to load a level at a time, without the need of loading, dynamically or all at once, whole gaming worlds, and this HW frugality is even greater in 2D platformers, the most successful Ninty ones.