Are you saying that MK8 didn't do much for the system?!
No it didn't really do much, it appears like it did but the fact that it released in a time that had a drought last year made the YoY boost seem bigger than it really was. If Wii U had a somewhat major game+bundle release in May/June 2013 then we would have likely seen a modest YoY boost like we have seen the rest of the year.
In the US Wii U is up YoY by about 270k thru November while Japan is down about 100k YoY in the same time frame. If VGC numbers are correct then Europe is up by a similar amount as the US. Worldwide Wii U is up by about 500k YoY in the first 11 months, percentage wise that's pretty decent but in terms of actual numbers that's not really huge considering this year had Donkey Kong, Mario Kart, Hyrule Warriors, Bayonetta 2, Smash Bros, Captain Toad.
When the herd loses its way, the shepard must kill the bull that leads them astray.