I'm going with 2016 (or by March 2017 at least). The Wii U's peak year should be 2015 since hopefully both MK8 and Smash combined will give the Wii U a new good baseline (MK8 has done a good job so far) for 2015, we get nearly 1 Nintendo game a month, and least but not least a price cut.
Bets:
1. If the Wii U sells closer to 10 million LTD by 1/3/2015 I win. If it sells closer to 9.5 million LTD by 1/3/2015 OfficerRaichu15 wins (winner gets 2 weeks of avatar control)--Lost.







