>>717809705 (OP)
Like everyone else says, Waterfowl dance is pretty much the only thing holding the fight back from being one of the best bosses in the series.
Normally, a move that punishes you for being too close is fine (see Manus's rage move, or Old Demon King's final burst)
But it can't be paired with an insanely short windup time, and enough damage to completely wreck most players if they get caught in it.
Oddly enough, there's a similar move that doesn't have a lot of windup time, and catches you if you're too close, but no one cares. Godrick's tornado attack. it starts with him raising his axe, and in less time than your weapon's wind-down animation, you're taking damage.
The reason no one cares about it is that it barely does any damage, and you get ample opportunity to dodge the second hit of the attack.
If you ask me, the way to fix the Waterfowl dance is to remove all tracking on the first flurry of the attack. Then the easy to figure out strategy would be to run sideways for the first hit, i-frame the second, and stand under her as she overshoots you for the third.
You could also raise up the windup timer significantly to give people a chance to run away even when midrolling, and in the middle of a weapon animation.