You can't use your shield to survive grabbing attack. That grabbing attack... From my 60 attempts 45 were one hit kill by grabbing attack. Shield doesn't protect against grabbing attack at all.
She even started her whirlwind attack close to me so I was forced to tank whole attack, or die. Last hit/hits went trough but I survived. The fight was beautiful, how these wooden stairs went on flame from grazes of her sword, and because I tried to find few seconds to drink estus and to avoid tactics that depends on luck, the fight wend three times longer than normal.
Are you actually mistaking whirlwind attack for something else? And doesn't Giant shield require something like loads of strength? I had about 18 when I fought dancer. I kinda had balanced character.
edit:
I could do dancer in only two styles, as long as I didn't want to learn her attacks to dodge them, it would distact from the story and feel too like fighting game where you beat one boss after another instead of fighting trough enemies doing quest and then find the dancer.
Either using shield, or as a mage. But as a mage, which I tried 10x, it would be very twitchi, and my hands would be shaking half hour later after I'd win. Considering I didn't wanted to risk heart failure by overdoing it, I used shield style where I could kill her more consistently, and I could use armor. (Actually I don't remember if I used shield, long sword, and master swordsman clothes because fuck that. Who want to change armor from my last mage attempt.) With mage I had strong problems to have enough blue estus to be able cast enough soul arrows to actually win. It's pretty harsh balance between enough estus for HP, and enough blue estus for casting.
The shield way is significantly more consistent when you don't have enough FP for casting reliably. It's true you can save FP in first phase, but...
It's actually easy to kill Dancer in first attempt, all bosses are doing all attack in the first attempt, ony in second they would use what's more efficient. When you remove 3/4 of health when they are not doing the best things, it's easier to finish it.
Dancer is strange in this case, because she can be really variable. It can be extremely easy, or as in my case when I killed her, she can have combats when she's extremely hard, chains nasty stuff, and combines attacks correctly.
When you encounter it in the more nasty state, you'd be screaming murder. The longer the fight goes, the higher is chance she'd do few these combinations which would murder average player. So going all in removing half of her health fast and finishing her before she has chance to do more nasty way of fighting, can happen, because she's not always doing her worst immediately in the start of combat.
I actually don't remember if I wansn't horribly underleveled. I was definitely under 60 because I did Lothric at level 64 and I was forced to level to that because he kicked my ass, because I summoned to have more funny fight, and summons were killed early, and I was forced to fight SIGNIFICANTLY longer. Fighting significantly longer in the second phase is death sentence, as long as you don't have proper dodging skills for Lothric fight.