Criticism regarding the Nanamo thing, I believe, is a big part of the reason that SE's been a bit more extreme lately, what with stuff like
Papalymo's death and Lyse's reveal and retirement from the Scions, Raubahn's retirement as Grand Company commander, and Minfillia's ascension and departure to another world.
Granted, most of those aren't deaths, but they are pretty significant blows to the status quo, nonetheless, and I don't expect any of them to be undone.
At this point, I don't expect any character aside from the WoL to have foolproof plot armor.
Y'shtola, in particular, has put up some crazy death flags with the whole "using this sight is sapping my life away" thing.
While I won't say I'm 100% convinced she will die, I do think that's something that is going to be addressed within the lifespan of the game.