Jean Grey wanted to eat planets? An alien planet she had never been to before? The Phoenix did all that shit another recent retcon, being in Jean allowed the guardian of the m'krann crystal feel volition and emotion and it tried them both, the beings immense power is what made it so fucking dangerous to be bonded with anyone mortal that had free will and morals because they weren't consistent. Even Galactus told off the phoenix for this post being linked with Jean Grey. The guardian of the crystal is supposed to be just that, because you know, thats the actual relic of power, not the phoenix...oh wait another convenient change. Jean ultimately died because she knew the Phoenix with ANY MORTAL BEING was too dangerous and the way to release it was to kill its avatar.
So yeah its still all recent changes to character , AvX was what 2 years ago , the other 60+ years of Sub Mariner in his own stories, marvel presents, The Defenders, Avengers and FF4 say that Namor has definitely been drastically changed, even if he did ultimately buy time for Doom to do his work.