Its not a port, they did change things under the hood and they are using the Ignite Engine (like Live, and FIFA, NHL will also be using it for the next gen version).
You seem to think that graphics were the most important thing about the move to next-gen, everyone on this site will disagree with you. Gameplay is what matters most, graphics should evolve with time but if the game doesn't play well then graphics are meaningless.
The game plays better and it looks better, you may not be happy with the leap in graphics but the gameplay improvements are more than enough to warrant the uptick in the overall rating.
This Port nonsense needs to stop, it's not a port plain and simple, if you want to argue that it is too close to the current gen in looks and/or gameplay, fine (I disagree, and I think the majority would say that it is an improvement with the only debate being how much of an improvement it is), but that does not mean the game is a port.