Do you mean you have first hand experience of (hand-)flying a 330 in ALT law2 at 35 000 feet ?
Of course not.
But I have experience that takes the observations out of the realm of pure opinion. (You're welcome to discount anything I say, that's fair, no problem.)
But I would not make general sweeping relativistic statements like:
"
Airbus pilots say the A330 is "difficult" to hand fly at altitude."
It's a big swept wing jet that
"handles" and accepts proper pilot inputs like any other big swept wing jet in comparable situations, regardless of the active law. Not a "balanced on a pin" new concept out of Area 51.