Navi seems to be compared to Pascal at most outlets. - You would think it would be compared to Turing? But I digress.
I remember reading somewhere that initially Navi was going to be the last of GCN and then Next Gen would be a completely new arch, but a decision was made to turn Navi into a hybrid between GCN and next gen to ease the transition process, which is also why Navi seems to be so far behind. It would help explain some of the rumors and leaks if true.