I've talked with a few friends and there's obviously I just fundamentally don't understand about the game here because apparently Ultimate Whirlwind Attack is useless and garbage.
But... I don't see how.
It's multi hit, you can cancel it at any time without using additional meter (and if that's not enough, you can YRC the Goshogowara for 25% meter if you are playing a really hyper aggressive opponent that can read you like a book), it does a LOT of damage (even when blocked it'll still do some serious chip damage) and even if your opponent Faultless Guards against it and times everything perfectly, they can potentially lose up to 20% meter just guarding from it, and if they try to jump out or they try to throw out a counter attack you can throw out Goshogowara (and, as said before, YRC that).
Even if you completely whiff it like a total wad and end up whirling off in the opposite direction of your opponent, at the very least you have forward momentum so when you cancel it you're not left in range of a quick jab.
And if you get every hit plus Goshogowara, it does a massive amount of damage. And this is even more important later in the game where single-hit overdrives will do miniscule damage thanks to proration.
Her Ultimate Whiner overdrive is a good multi-hit for the same reasons, but it's significantly less safe on block or whiff (not that I'm saying whirlwind is 100% safe on block, just safer) and doesn't even do any chip damage if it IS blocked so it's just a waste of your tension meter and a great way to give your opponent an advantage in a match.
So I reiterate... what is BAD about the Ultimate Spinning Whirlwind and Goshogowara Attack?