gillybob, There is no doubt that if Diana had lived she would be number one grandmother but if she had lived, we could be looking at an entirely different set of circumstances.
William might not have gone to St. Andrews, might not have met Kate and if he had, would Kate have wanted to be in constant comparison to a needy mother-in-law? William might not have a child (yet) and Charles would, almost certainly, not be married to Camilla.
I was not a Diana fan and she was definitely a loose cannon. While she might have cheerfully indulged in winding up Charles I don't think she would have deliberately done anything to discredit the Royal family of which her son would one day be head.