What can we expect?
I mean, XM3 sound quality is already "nearly perfect", so there isnt really anything major to improve.
I have had them for +2 years and they are still so good.
Headphones are so old invention by now that they are kind of perfected in sound quality, if manufacturer chooses so, even on cheap models.
ANC could be improved, but even that have physical limits of how good it can be.
Anyone whom expects big improvements on sound quality is just getting dissapointed(because they are so good already)
Call quality and touch control that goes ape shit crazy on warm enough(it mimics finger swipes when bicycling around +20C) and when it is cold enough are my complains.
I have dropped mine on concrete/asphalt from 1-1.5m multiple times, only scratches so build quality is great.
And comparing to 3000€ hifi headphone sets is useless as they have more of psychological effect than real sound quality differences. Like those idiots that pay thousands for speaker cables or even hdmi cables and claim they hear differences
(if someone claims that those have much better sound quality)
Expensive stuff can sound different, but it doesnt mean it is better.