PSVita was at 621,578 unit sold at this point of the year in 2014...

That's -25% dropped.

Considering PSVita sold 1.17m in 2014, with this trend PSV is going to sell 880k in 2015... What do you think will sell this year and in the nexts year?

I can understand what Outlawauron is saying.  Vita had an abysmal final quarter last year with a poor showing at TGS; no big release other than Phantasy Star Nova which underperformed; and no change of circumstances.

While it's just speculation at this point, any price cut/hardware revision this year would make the last quarter of this year look pretty different from last year. It'll have been 2 and a half years since the last price cut in Japan and 2 years since the last revision.  KanColle is a bit of a wildcard in terms of software too.

As things are right now, you're correct in that the trend of sales will continue to go down, it's been on a downward spiral for a while.  All the more reason for Sony to step in and do something about it.  Whether they will or not is another thing, but I can see why people would be presuming that they will.

For the part about the super first quarter sales: that's normal.

Is qlways so with the PlayStation console in Japan: the first quarter is super strong, the rest of the year not at this level.

Is happen for Vita last year, is happen again (indeed Vita was 20-30k costantly in January-March, now is just above 10k), and even for PS4, it was selling even +40k in some week...

Of course is even a question of games for both PS4 and PSV, but still, you can see how is ALWASY strong the first quarter for the PlayStation sistem... i expect as well PSV and PS4 to back at +30k in March 2016, and then dropped at 10k by April...

The same in the other countries, for example the US, in February / March PS4 is easy above 300k for the month, but by April even 200k is hard... (152k the last month)

Any way, let's see. I was wrong about PS4 and PSV under 10k in 2015.

A pricedrop can help of course. KanColle and the other games also. Maybe >1 million in 2015, but i don't think will be up YOY...

I do agree with the strong Q1, but the thing is, Vita had a strong Q4 in 2013 too (God Eater + Vita Slim + VitaTV + FFX for the final week).  Compare that to 2014, it's a whitewash.

Personally, I think 900k is a good enough estimate.  I can't see any situation where Vita is up YoY.  It might be able to push 1m with a bit of help though.