Of the faces we see of characters who are definitely dead in the teaser, only Joffrey isn't a Stark (at least if we include Jon Snow as a Stark, which for purposes of this I am, although there's more reasoning behind that I will get to). While it's likely it's just showcasing the big death from each season - Ned in Season 1, Robb and Catelyn in Season 3 (with none for S2), Joff in S4, and Jon in five. But also it's noticeable that these are all Northern characters (again, except Joff), and it's another example of this season seeming to be heavily weighted in favour of the North - if there's any doubt, just look at the casting announcements. I've wrote more about this here, but with the Northern focus and the return of Jon Snow, it seems that the North not only remember, but they've cooked up a rather grand conspiracy.