It's just been confirmed. I do like viking stuff but I'm not sure how it will fit in the lore of the series. Not to mention that big cities back then were pretty small especially in Northern Europe.
The good thing is that vikings were big on exploration and they were more than brainless raiders. They were devious and trickery was one of their most efficient weapons so the whole cloak and dagger stuff could work in this setting.
My major concern is that we've had so many viking games and TV shows and everything so it's hard to feel hyped about a viking Assassin's Creed game. I guess piloting a longboat could be nice though.
I read there will be loads of customisation and the possibility of playing a female character and that's a relief because I'm really not thrilled by the main character's looks (nothing positive came to my mind when I saw that character looking like a WWF reject).
The main team working on this game is the one who was responsible for Origins (and Black Flag before that) so it's looking good.
Last but not least the eagle is going to be replaced by a raven and that's very fitting considering the setting.
"Growing old is inevitable but growing up is optional."