Today Saints Row 3.1... uhm I mean 4 was announced to be released in Fall 2013. Which was expected.
http://www.gamrreview.com/news/89872/saints-row-iv-announced/
But even tough Saints Row 4 is a multiplatform title it is not comming to the WiiU.
http://www.polygon.com/2013/3/15/4108432/saints-row-4-is-not-coming-to-wii-u