I just look at the huge spike that Pikmin and Wind Waker HD gave the Wii U for a little bit, and have to believe that Tropical Freeze will give an even bigger spike.  DK is a bigger seller then it gets credit for.   DKCR on Wii sold  3.5 million in its first 6 weeks and is now sitting at 6.1 million.  The port on 3DS is at 1.25 million, which to me actually show's DK's selling power even more.   A port of the exact same game on Wii has outsold Fire Emblem Awakening, Starfox 64 3D, Pilotwings, Mario Tennis Open, Kid Icarus Uprising (This one suprised me),  and is currently sitting at 19th place on the 3DS list.  Tropical Freeze is also going to out pre-order SM3DW by alot.  Donkey Kong hasn't been overdone by Nintendo in recent years by any means and that will make a difference.

Donkey Kong Country: Tropical Freeze (WiiU) 4,454 86,329

Doesn't seem that much for a game to be released in 3 weeks and with a talked about potential... Either way, I'd be happy to see WiiU gaining more sales.

Especially for a game that comes after the biggest selling time for Wii U.

Nintendo games aren't really known for their pre-orders, Super Mario 3D World was at less than 50k at this stage prior to its release, Pikmin 3 stood at 76k.

I'm one of those people that doesn't bother pre-ordering a game that I want on release day. Usually I just walk into Best Buy and there's a shelf full of copies for whatever game I'm buying Day 1.