Didn't work for me with DS1 unless I missed something (can X360CE mask Dinput commands?) so YMMV. Seriously.UPDATE: I bear great news! DS4Tool wasn't working for me, so I did some Googling and found a guide which was made for Dark Souls. I figured I'd try it for Dark Souls 2, and to my great surprise it worked!
In other words, I'm confirming that you can in-fact use your DualShock 4 to play Dark Souls 2 on PC!
Instead of using DS4Tool, download X360CE and place it in your Dark Souls 2 Game folder (for me it's C:\Program Files (x86)\Steam\SteamApps\common\Dark Souls II\Game). The guide is below.
http://en.reddit.com/r/darksouls/comments/1pluy3/how_to_use_a_dualshock_4_with_dark_souls/
God speed compatriots.