Release in novermber 18-20 this year apparently.
http://blog.ubi.com/far-cry-4-release-date-kyrat/
Ubisoft description
"Far Cry 4 is set in Kyrat, an untamed region currently ruled by a despotic self-appointed king. But don’t be lulled into a false sense of security by the achingly beautiful views; Kyrat is a wild land full of perils. Once again, players will be able to craft their own stories as they travel through this exotic open world teeming with wildlife – using their wits along with an assortment of powerful weapons and diverse vehicles."
i don't expect huge change in 2 years from far cry 3 release (2012), but that game was pretty good, so more of the same is not a bad thing for now, as far as i'm concerned.
EDIT forgot to mentioned, it will be available on XB360, PS3, XB1, PS4 and PC. So it's still a cross gen game.
No Wii U version though. Looks like Ubisoft had abandonned the Wii U for now.