I'm part of the crowd that can't even play it anymore. It crashes when I try to load a save or a new game. Exits to desktop without any crash notification.
Tried updating all mods, checked order, disabling all mods except official ones, verified the game on steam, all drivers are updated, disabled steam overlay. Even tried the various window compatibility modes, no difference. Worked fine before Far Harbor was added.
Only change I can see to add to the problem is between windowed and full screen mode. When using full screen I just get a black screen where my computer locks up with a black screen and a loading icon. Have to close the game from the task manager then. In windowed mode, it gets to the menu, but quits when trying to load.
As I stated in the steam forums, I think Bethesda should be able to afford a new engine with all the money they save on not bugtesting their games, dlc or patches.
Apparently the DLC is also filled with crash bugs for both PC and PS4 for the people who can actually launch it.