Here's my prediction. Post yours in the comments.

Wii U had a tough first half of 2014. Selling nearly as bad as 2013. Mario Kart 8 had come and has boosted Wii U sales for 2 months now and has had a steady baseline for awhile of 60k. If this keeps up it should hit 7 million in about a month. Which is going to be the very beggining of September. When will it hit 8 million?  By September Wii U baseline should drop just slightly to 50k-55k. Probably will sell 250k because of Hyrule Warriors at the end of the month. Puts Wii U at about 7.3m... Now lets go to October.... Probably will have a very small boost to baseline.. selling about 65k to maybe 70k. So lets say 67.5k. Now with Bayonetta 2 at the end of the month.. it will give it a small boost. Wii U will probably sell just short of 300k in October. This puts Wii U at 7.6m... Now November.. it has 5 weeks.... Smash Bros will probably release in mid-late november. Along with Sonic Boom and Captain Toad Treasure Tracker. November I think will top 1,000,000 because of this. Maybe even a bit over. and Black Friday and getting close to holidays. Wii U will have sold 8.7m... December.. the largest month in terms of sales. Probably will be 2,000,000. Putting Wii U at 10.7m sold..... There's not a doubt in my mind it can't hit this. It did nearly 1.76m in Dec 2012 and 1.14m in Dec 2013.

EDIT: I forgot about Amiibo.

is a safe bet

I would say that 9million is a certain - though for 10? Random guess : 93% chance - depending on the effect of Amiibo's and how much Hyrule Warriors sells.

Edit: Actually seeing your brakedown with those quite low boosts Sept/Oct (and not exactaly mentioning JPN releases this month and B1/2 a month earlier), I really think this is my prediction:

10.4 Million!!!! =D For comparsion, I think PS4: 15.8m and X1: 8.0m

11 million is possible. My prediction is 10.7 million. Selling an extra 300k isn't impossible,

Most probably, though Holiday months will be the major decider, if the console was able to do almost 1.5 millions, with only a game that is a mix of 2D and 3D Mario, it should do waaaaaay better, with Mario Kart, Super Smash Bros, and a new Zelda game, even though a spin off, plus a diversified library, even with the PS4 and Xbox One around, the Wii U should atleast do around 2.3 million.

possibly but I wouldn't bet on it.

If everything goes right for Ninty, then yes:  Amiibos being a big hit; $299 Smash bundle; big Hyrule Warriors reception in Japan; top-tier advertising.

I do think so with Smash and the other titles... Its a much better lineup than last year and mario kart 8 is still a reason to buy the system.

Great point - now my hopes are starting to make me feel confident about them.

2M will be a most probbable situation. I want it to happen actually.Wii U's 2015 (the huge important year) will be much better with that 10M reached already.

I doubt that the WiiU will reach 10 million total by the end of the year although it is hardly impossible. If Nintendo can maintain the momentum that Mario Kart 8 won them it might become a reality. However, I predict something closer to 9 million by year's end.