'Virtue and depth never experienced during her life' Lady Nimue? Well, I happen to believe that Diana had great compassion for others and was therefore the reverse of shallow. I also feel that she possessed virtue as in excellence or a good quality.
The second bolded first: if I understand you, I think you are equating perhaps her exterior breeding (excellence) and dress (good quality) as a 'virtue'. Not sure, but it falls far short for me. While such is compelling and charismatic in the moment, I would be more impressed with her had she made her choice (marrying the heir to the throne) and taken on her historical role with class, discretion and decorum. She didn't. She simply never impressed in that way.
For the first bolded, she was a complicated lady, let's put it that way. From what I read she could be utterly charming one moment, and utterly unpleasant the next. I'm not up for splicing and dicing Diana's reality, but it's there for anyone to see who wants to look. To me there was not a lot of virtue, but she for sure had her 'good' compelling points. Depth is always a personal call. Someone like her who can shift between moods so quickly is just not my cup of tea. I am especially not keen on public heavens and private hells. Been around them too much, I guess.
Diana did not have the time to finish growing and maturing during her short time on this earth as she was taken from the world to soon.
Being around Diana's age right now I am a bit nonplussed with comments like these. I am plenty mature at my age: I am married with children and a career. I handle my household, plus elderly relatives, and much more. Why Diana required so much 'growing up' I will never understand. Her behavior was, pure and simple, strange by any standard. Look at the videos. We all see something different, I guess.
BTW when I said she hadn't matured, I meant in the physical sense. I meant that the image of her is still from her prime. She never aged in front of the cameras. She is an image in amber. Any photo composite will always be misleading and a bit spooky because of that.
Besides there really is no time table on when a person matures in life, that is done through experiences in life only. All that we see today are the pretty pictures of a very beautiful yet troubled young woman who had great love for her 2 sons and compassion for others as seen in the many pictures and news articles that are still out there today.
Well, that's for sure. I'll agree there. The limitless patience accorded Diana by her admirers is impressive. We should all have the grace of such patience accorded us. Consider the irony, though, that everyone else in that story is suppose to be older and wiser and know better. At 30 Charles should have known better, but Diana at 30 just needed more maturing. It's all a very curious phenomenon, and gets tiring. If I never read another Diana book it will be too soon.
I've reached that point.
[
Edit: Regarding maturation only happening via experience: I am going to disagree. There is such a thing as metaphorical thinking. There is such a thing as learning from the experience of others. My understanding is Diana read a great many Barbara Cartland novels, and not much else. It's through reading that much of our 'experience' gets deepened and our sophistication gets expanded. It's why Charles attempted to interest Diana in reading beyond just the romances. Had she welcomed his overture, she could have expanded her horizons and become more cultured rather than just an icon. With wider horizons she may have been spared her failures and heart-aches. Just an idea.]
The one thing that I know for sure is that Diana loved her sons more then anything or anyone on this earth and that love is still out there for all of us to see and enjoy today in the living proof of how well her sons are doing.
My last comment: Diana's love for her sons was undeniably genuine, we all love our children. But I would argue she might have loved herself more, or been unable to untangle her own needs as distinct from her children's needs oft times (examples of this are myriad). And saying this, I don't exempt myself from such failures. As for how her sons turned out, it may have much to do with experiencing their mother's deep, tactile love, but also to do with the solidity and regularity of royal life (which includes schools and teachers), and long vacations in nature protected from intrusive eyes, by a vigilant father.
In the end, this, too, is Diana's legacy: the controversy. It is a legacy that will never fade away. It will all be re-hashed again and again as new people come to the story and read the details, the way people read about Queen Victoria and Prince Albert and 'read into' the contemporary accounts what they will. Diana will always be there. She will shadow George and Charlotte and any other children of William, and Harry. Just as people see Queen Victoria in Princess Beatrice, so will people strive to see Diana in future generations. Not everybody, of course, but those interested in history of a particular kind. Most of the world will move on, as they already have. JMO.
Definitely entering the twilight zone there! 
She never aged, and in a way, never matured, she continues as a fantasy. Even after all this time the reality of who she really was simply has not penetrated for some. The glossy image remains forever, within which there is virtue and depth never experienced during her life. The 'legacy' is outsized, far beyond anything she did when alive. 
