Rocksteady may have given the impression that they have given up on the PC version of Batman: Arkham Knight but luckily this is not true. Recently an update has been rolled out that is said to fix a number of the games many problems. This update will be fixing multi-monitor bugs, smoother keyboard and mouse bindings and an improvement of VRAM management.
Batman: Arkham Knight has many problems on PC and Rocksteady are definitely working there hardest to fix them, check out the full patch notes either on Steam or clicking the source.