The title is coming, but WayForward isn't rushing.
Mighty Switch Force 2 will come to the Wii U eventually, although currently there is no huge rush.
The developer WayForward has told Nintendo Everything that, "It's kind of a backburner project right now." Although, WayForward hopes to make an announcement sometime over the next few weeks.
Mighty Switch Force 2 came out on the Nintendo 3DS in June. A PEGI rating revealed a Wii U version about one month later.