My whirlwand is always cancelling for no reason !
Is it possible you’re running out of fury? That’s the only thing that should stop you, unless you’re getting CC’d when WotB is down.
With BK weapons and Whirlwind runed with Wind Shear there’s no way you should be running out of fury. Looking at your abilities, the only thing I can think of is that you’re spamming Sprint and/or Battle Rage. You do have a few redundant Attack Speed affixes on your gear which won’t help so, having said that, you’ll probably find this useful…
Is it possible that this is like that other thread about WW Barb that is actually in PTR with a 4th cube item draining fury?
If they’ve got Echoing Fury in the 4th Cube slot, maybe.
What I found was, if I happen to move my mouse over something that is not in the field of play on the screen, it cancels the whirlwind, since I have it on my left mouse button. Maybe that is happening to you?