It gets worse - Batman: Arkham Knight on PC lacks console visual features - Digital Founrey

Just as baffling is the fact PC lacks key visual effects seen on PS4 even at its top settings. Ambient occlusion is cut from the game, bokeh depth of field is noticeably dialed back, and the transparency layer used for raindrops is cut from all surfaces as well. Gotham City is stripped of a great deal of atmosphere as a result

Likewise, rain doesn't appear on Batman or the Batmobile as it does on PS4.

Part of the deal when you're a PC gamer (which I am not) is that you get to play the best-looking versions of every game that comes out. It's madness that not only does the PC game run terribly on most systems, but that it also doesn't even have some of the advanced visual features of the console release.

They round out the article with this brutal conclusion:

With its crippled frame-rate, poor streaming, pared back feature set and bloated minimum and recommended hardware spec, Arkham Knight is bitterly disappointing and should never have been released in this sorry state. There's a massive amount of work required to get this version of the game into shape - as things stand, the experience is totally unacceptable.