One thing that has made me respect Charles increasingly as the years have passed is the way he successfully navigated the boys' lives after Diana's death. He didn't make them give up all connection with their mother or the causes she was associated with. (Contrast this with the otherwise wise and delightful Theodore Roosevelt, who wouldn't hear of his dead wife's name spoken ever again. Unfortunately, she was the mother of his oldest daughter, Alice. Wonder how that made Alice feel amid second wife Edith Carow's five children?) Charles managed somehow to give his sons a protected childhood but also to give them opportunities to go out into the wider world. He also managed to continue a relationship with Camilla in a way that made the boys comfortable. I hope the sons do like Camilla. I'd like to think that everyone in that family has found a path to peace and happiness.
What the queen thinks and thought about Diana should be her own business. I liked Diana for herself, but as I said earlier, she was probably not easy to live with. The truth is that she didn't belong in that family: it was a terrible fit. This despite the fact that she came from the aristocracy and was presumably as familiar with the royal world as anyone could get, so she had a bit of a head start in terms of adjustment. We can't know all the details, but it seems as if there was enough blame to go around. Charles married her without giving up his true love. Diana was starving for attention and behaved badly at various times throughout the marriage. Charles probably closed her out of his affections in every way imaginable. Diana gave that interview.
And then once she was outside the royal bubble and couldn't be protected or guided, she started dating unsuitable men and generally roaming around Europe like cafe society. I'm not all that sure she would have found her way to a satisfying life had she survived and aged. Though if she had, she'd have been quite a force for good in the world. As it is, she lives through her sons, but they shouldn't be compelled to feed the public's need for some Diana connection every time they're interviewed.