Assassin's Creed 4: Black Flag trailer shows fancy PC-only effects

Assassin's Creed 4: Black Flag has been pushed back on PC to November 22, but why?

has been pushed back on PC to November 22, but why? Are PC push-backs so coded into Ubisoft's DNA that they can't physically stop themselves delaying things? Are they adding more beards to the piratey assassin adventure? Perhaps they're fine tuning the collection of smooth PC-only effects demonstrated in a new Nvidia video, invluding a TXAA mode that removes flickering jaggies during camera movements, and god rays. Caribbean god rays, no less, which surely need to mature in a luscious tropical paradise for a while before being allowed near a finished game.

There's also a HBAO+ mode, which means faster and smoother HBAO for the refined HBAO connoisseur. Oh, and PCSS, though it's better to watch the video below to see what that is. Now excuse me for a moment, I have bits of alphabet stuck in my teeth.