C&C have definitely gained popularity. Now I'm not saying most loved, but they have crawled up from the relegation zone.
Thing is the "events" that made him unpopular were all whilst he was a younger man. He's now in his 70's and for the past 25-30 years has kept his head down and just ploughed on quietly. This has earned him "points".
For some who weren't even born when the "events" occured, they have liked him for his environmental causes and accept he's the next in line and will be King withing the decade.
I mean I was 5 when Diana died, and having read back on it all seems both were as bad as eachother in the marital affair scenario. They were pressured to marry, she was too young, she was unable to cope because of her mental health, she wasn't given any support, but once splitting from the family courted the press, refused palace security and tragedy followed.
He had a longstanding affair with C, and if they (the firm) had just let him marry her none of it would have happened. He's loved C his entire adult life. You can't help who you love.
And the same goes for H and M they clearly love one another, that's obviously fine, but they now just need to cut ties with the UK and forge ahead in the US on their own without anymore tell all books and interviews, let the dust settle and crack on with their life there. They would be happier for it I'm sure and concentrate on their charity work.