The issue is that Retro doing effectively DKCR2, and that is one of the underlying issues with Wii U's first party lineup: nearly every game is an iteration of a previously-released Wii or 3DS game. They can be good or the best games ever (see reception of SM3DW), but that does not convince certain people to be interested about the platform...especially since the last platform ended up with dropoffs of support four years in.

Retro making Tropical Freeze is not bad, but in a time when Wii U needs something more than "we got sequels of Wii games in HD" to get more people interested, announcing TF was probably not the best move.