How good will PS4 version be you think...?

[Shioban]

PS4 is a DX 11 console so it Xbox one.

Nope.

The Playstation uses OpenGL, DirectX is a Microsoft distributed and licenced set of APIs, therefore it's not used very often for PS3/4 development, it's easier just to go with OpenGL for the most part.
HOWEVER, the PS4 is changing that, the hardware makeup has completely changed this time making it substantially easier to code for the PS4 meaning more developers might butcher around with DirectX11 instead of OpenGL.

With the OpenGL/DX11 update for PS4/PC

All the things Square Enix have at their disposal for use are;

•General performance improvements through hyper-threading options,
•Higher Quality/Stronger Shadow/Light Casting
•Higher Quality Screen Space Ambeint Occlusion (SSAO)
•Better multi-core processor support
•New shader rendering types/options
•Transparency rendering/filtering/sorting improvements
•Dynamic LoD based Tessellation (Water included)
•Improved Animation Smoothing
•Parrallax Mapping (Occlusion)
•Improved Ray-traced Local/World Reflection/Refractions
•Dislacement Mapping
•Much better particle rendering performance (I.E more particles) that can even cast shadows.

BUT MOST OF ALL

DirectX 10/10.1/11 supports Hardware Based Anti-Aliasing with Deffered Rendering which is the real-time lighting/shadows system FFXIV uses.
Currently FFXIV uses FXAA (Fast Aproximiation Anti-Aliasing), as due to the way (if I recall correctly) the way DirectX 9 renders the Z-Depth the hardware based anti-aliasing is defeated leaving an odd/unintended effect, therefore Square Enix dropped Hardware based Anti-Aliasing support. This issue was fixed in DirectX 10 onwards, it makes HUGE difference to the game when you can use hardware based anti-aliasing as opposed to a software based filter overpass.

Hardware based transparency Anti-Aliasing also makes a huge difference.







All of this being said, Square Enix clearly aren't going to use all if even half of these, but they are options avaliable for use at virtually no performance cost to the players that can garner improvements such as these.
Most are easily added as a toggle, and easily added in as 'optional extras'.