Vibration on Windows is a weird beast at times. I always disable it in FFXIV because it causes the game to either crash or become unresponsive to input when it rumbles. This is using an official Microsoft Windows XBox 360 Controller and had caused the same issues in DX9 & DX11 versions of the game on Win7, Win8 & Win8.1 (all 64bit versions).

It's easier for me to do without than risk corruption from a crash.