It is interesting that Ghost Games is using the same Frostbite engine that is being using by DICE in Battlefield 4 which is running at 900p on the PS4 and 720p on the Xbox One and upconverted to for output at 1080p.
The reality is that it takes time to optimize your engine for the new consoles and developers need time to get the best out of the console. As we have said we have little doubt that development will get there and learn how to put each console in the best light possible.
We will have to see how things shake out, but we expect major revisions to the system software on both consoles over the next several months which will add more features and better performance. It is just the nature of things.