Right, firstly, FFXIII was PS3 exclusive right up until E3 last year. Yes, SE had probably dabbled with the 360 with regards to FFXIII, but up until that point they had been developing the game with the PS3 solely in mind. This is different compared to other games with PS3 lead seeing as they were developing on both platforms but decided to lead with the PS3 seeing as it's the most sensible way to get similar looking and playing games.
SE games are notorious big and I can see this posing a problem first and foremost. Not don't get me wrong, I doubt the differences between the 360 and PS3 versions will be huge, but have a 2 year development on the PS3 first and foremost before even touching the 360 version will have it's positives.
Also don't forget that the 360 and zoned PS3 version won't be done until the Japanese version is complete. Add to this the statement that the demo released this week is supposedly 50% of the performance they expect from the PS3 once the game is released.
They must be differences unless SE pull back on what they intend doing to make sure both look as good.
Prediction (June 12th 2017)
Permanent pricedrop for both PS4 Slim and PS4 Pro in October.
PS4 Slim $249 (October 2017)
PS4 Pro $349 (October 2017)
