Mario 3d World, Mario Kart 8

No, mario maker is.

Mario maker is everything that went right with the gamepad. An excellently polished game that utilizes the gamepad in a non-"forced" yet substantial way. A classic for anyone of any age. Intuitive for any newcomer, yet potentially tough enough for all the serious players. Refreshes the mario 2d line while adding nostalgic artstyles and gameplay from the titles we grew up with.

Splatoon is a good game. Nothing revolutionary (especially with regards to the gamepad), just a new ip that had its ups and downs

Splatoon and Mario Maker.

How can it not be?

Splatoon is no less revolutionary than Mario Maker. After all, one could argue that Mario Maker is just Little Big Planet with an easier UI and set in the Mushroom Kingdom. It's been done before. 

I think both games will be the 1/2 as far as what we remember about the system, but Splatoon is a NEW IP. So it will likely stand out more.

mario maker too. splatoon and mario maker are phenomenal games and can only be done on the wii u.

Mario Maker to me will always be the game Nintendo should've launched the system with.  The Wii U might currently be in a way better situation if that happened since it does everything you said it did and is more interesting to gamers and casuals in comparison to Nintendoland (basically a fairly boring retread of Wii Play's formula except it uses the gamepad and Nintendo characters).  That being said, Splatoon will be the defining game of the Wii U.  I'd throw out the reasons why I think this but other people have basically said everything I would have.

It certainly will be for me, as it should for everyone!

Indeed. I honestly forgot what was the last new IP from Nintendo which performed this well!

Yes. It was the biggest sales suprise of this generation and the second best system seller for the Wii U.