I'm continually amazed by how Splatoon has seemingly shifted the Wii U's baseline singlehandedly.

Though I do think we should give some credit to the other releases this year (Xenoblade X, Kirby, Mario Party, Yoshi, etc.) which I'm sure have raised consumer value for the console. It'll be interesting to see how much of an impact the later releases have, which are no doubt bigger than those from the first half of the year (aside from Splatoon, of course).

It's awesome to see that the Wii U has consistently managed to stay above 10k for such a long time, although I fear that the winning streak may come to an end when next week's numbers come up and they show MGSV's debut and a huge spike in PS4 sales.
I think those might eat into Wii U sales considerably and cause to fall below 10k for the first time since May.

Very much doubt it. The console  was up on Amazon Japan most of the time, while Super Mario Maker is coming the week after, which already can pull the sales slightly up

Amazing how Splatoon alone carried the Wii U in Japan through this year, well deserved recognition for that little gem of a game, hopefully Super Mario Maker will be able to help keeping the baseline where it is now, or even improve it a little.

Splatoon is the best proof that games sell consoles. Fresh and exciting games at that. I've said it before, but thank god Nintendo realized what they had on their hands with Splatoon and gave it the marketing push it deserved too.
WiiU in japan gives a great value this year, with Mario Kart, Smash, Splatoon, Pikmin etc. and Zelda coming up next year.

I've been checking the Weekly charts for Japan from beginning of September to the end of October for 2013
And the trend is that it decreases weekly to the point where it is at 2,806 units on the week ending October 27th... Very, very sad actually. And then the first week of November it spikes to 39,943, (Week the New Super Mario Bros. U bundle launched). Then it dropped to half the next week and then the holiday season took over from there.
So from now to the end of the year will certainly be interesting to see how 2015 stacks up against the other 2 years.

2015 + on 2014 will be a good achivement

That decrease won't happen again this year, it was due because there was basically no game releases in 2013 and exactly the same in 2014 between Hyrule warriors at Obon Week mid August and Smash Bros in November. There was Bayonetta 2 in between, but that's a game for the western market and didn't do well in Japan, while there was next to no anticipation for Smash due to the 3DS version.

The Lineup this year is much, much stronger for Japan, especially SMM and SMTxFE will push the sales up way in front of last year, Animal Crossing will do similarly well, Star Fox and Mario Tennis can also give some nice but more limited boosts. And then there's still Splatoon, which has a shot (Ha!) to become the bestselling shooter in Japan of all time this year.

In other words, as it had been said before, 2014 is done for, it won't come close to 2015 sales ever again, and the battle that's left is between 2015 and 2013. That one will be a tough one as the Wii U had a strong finish that year due to New Super Mario Bros U and a tax increase in January, so everyone tried to get the console before that date.

Updated again, within the next 3 weeks 2015 > 2013

WOW.

Wii U over 10k in both Media Create and Famitau, with Famitsu actually giving out worse figures this time, go figure.
15k+ Wii U for Super Mario Maker week?