I have flown the 787 a few times now. Generally on flights to/from Australia to Europe with a Middle East stop. All company paid-for flights sitting in business class. The 787 does the ME-EU legs, which are 6-7 hours, and the long haul from Doha to Australia is usually a 777 for 10-11 hours.
I initially couldn’t notice a difference in cabin humidity with the 787 either and sat back thinking this was a bit of a marketing story. Then I realized that I when got off the 787 leg, I felt as if I hadn’t yet been flying. Odd thing to say and feel. So the next time I flew with a 787 it was from Germany to Doha and I observed more closely; when I got off in Doha it really was as if I was still waiting to start flying. I felt pretty good. Absolutely fresher. The subsequent 777 leg to Australia made me realise that non-787 aircraft DO make me feel like I am flying !!
Then just after that, I had a flight where the EU-Middle East leg was flown with a 777 and not a 787. And oh boy, when I got off in Doha I could feel it. So I do think that there is a difference with the 787 in terms of feeling much fresher. Ok, I was lucky enough to be at the front and I can’t comment on the Y class experience yet.
A good thread though - I will take a look at Ethiopian next time I fly that way.