Concluding, i predict 4 - 4.5Mil Vitas sold during 2014.
Am i nuts ? thoughts..
Vita in 2012: 670k
Vita in 2013: 1.14 million to date (Week 51)
Vita in 2014, 4-4.5 million? Really?
I do think you're nuts with that prediction. Especially given that the first game you've listed as evidence of a strong lineup for Japan is "GR2", which I assume is Gravity Rush 2 - a sequel to a game that sold about 90,000 copies in Japan, on the PS Vita. And while Monster Hunter might help the system to sell a little more strongly, the problem arises that the "main" Monster Hunter games are now on 3DS, where it's selling well, and the new Vita game has already been released on Windows, Xbox 360, PS3, and Wii U.
J-Stars Victory VS (I assume that's what you meant) is also on PS3, which has a much higher install base in Japan than the Vita, so it's not likely to drive sales. And as with Gravity Rush, Soul Sacrifice is already on the Vita, and didn't sell nearly enough to result in such a large result in 2014 with the sequel.
I do think Vita will do better in 2014 than 2013. But I see nothing releasing for the system that would come even close to driving sales of the system as high as 4 million units. And the 3DS isn't anywhere near saturation - the Gameboy and the DS each sold around 33 million in Japan, and the PSP sold about 20 million. If 3DS sales are down YOY, it's because, of the top seven 3DS titles in Japan, five were released in 2011 or 2012, and 15 out of the top 20 were released in 2011 or 2012. Meanwhile, we don't know all that much about the 3DS's 2014 lineup, so predicting its performance is difficult... but I don't see it dropping below about 3.5 million, a number that I can't see PSV achieving, given the aforementioned comments on its known lineup.
So unless there's some major unannounced PSV titles that will sell hugely in Japan, I just don't see it being the best-selling handheld for 2014.