Currently, whirlwind creates about 1 dustdevil per second with the Dust Devil Aspect. Where as the double swing with increased attack speed can create about 4 per second? Although the damage from the aspect is greater than that of the Double swing, it doesn’t compare with the reduced frequency. This needs balancing. Whirlwind’s dust devils frequency should be increased slightly more, either by attack speed or by the movement speed of the player.
I think tying movement speed with whirlwind to modify the damage or frequency of dust devils spawned would be a good idea.
Edit: I know that if you spam the ability it creates more dust devils instead of channeling. But rereading that sentence seems counter intuitive of what the ability is.
Testing the Devilish aspect that “after generating 100 Fury your next attack creates 2 dust devils”, I even generate more fury while spamming whirlwind vs channeling it. There doesn’t seem to be any reason to channel whirlwind besides the Dire Whirlwind aspect. Which, even with a 24% increase crit doesn’t match the DPS I do while spamming it.