With Kasumi vs Ayane that is a 5-5 match up and it's been like that since doa4. That match up solely rely on spacing or lack of. If ayane cannot keep Kasumi out, ayane loses the match up. Ayane has nothing to deal with Kasumi's speed in close quarters. If Kasumi cannot get in ayane, Kasumi loses to the plethora of ranged options ayane has at her disposal.
Don't believe the hype that ayane or any other character that can space well will keep out characters all day. When played at their peak, the Kasumi player knows how to get in and stay long enough to win and the Ayane player knows how to keep Kasumi out long enough to win. Which ever player works their angle the best wins. So you have a 5-5 match up their. That's not unfavorable for Kasumi, sir, but rather fair. What's another character you think she an unfavorable match up with?
You should listen, Pai's damage is dead on. 66H+K is also a whiff punisher. On CH you're put in a sit down stun, free launcher, I take about a quarter of your life with me. You hold standing or crouching, I take over a quarter (107-130 pts) of your life with me. You try to be a smart ass and not hold out of stun to avoid being thrown, P+K or 66H+K into an unholdable stun, I take a quarter of your life with me. This not a theory, you are welcome to play me at any time.
Oh yeah, like Kasumi, Pai is relaunching you back into a wall after a wall splat. So, I slam you into a wall on anything but NH, I take a quarter to over a quarter of your life with me.
Her damage is dumb and she really doesn't have to work too hard for it, not in the slightest. Unless you're playing against a heavy weight, there shouldn't be an issue getting to Pai's damage.
Half her holds either guarantee a hit which extends the stun, where she is Jesus Christ at. Or gives her frame advantage, enough to make players think twice about hitting a button. The other half you're getting launched for free.