Great stuff. I grew up on Duck comics, and Barks and Rosa are clearly the best of the bunch. In fact, I sometimes find that I enjoy the funniest and most exciting Don Rosa stories more than some of the one Carl Barks did. They can both be pretty variable.
In my opinion Rosa's biggest flaw, at least in his later stories, is that he's completely committed to his continuity and his conception of Scrooge's character, to the exclusion of any personality traits he deems "don't fit". Barks always took a more flexible view, and would change things around to fit the story (or just for a good joke), even if it would seem to contradict other stories. In addition, Rosa gets pretty indulgent in doing stories that do little more than illustrate his three major Uncle Scrooge insights: Scrooge's real fortune is his many memories, Goldie was the great love and the great "could have been" of his life, and behind his facade of greed and tightwadness, he is extremely fond of his family. Those themes worked much better as subtext, or as small giveaways in his actions, than when he spends one and a half page tediously explaining it, like in "A Letter from Home".
For all that The Life and Times of Scrooge McDuck is his great achievement, I think I'll always prefer the standalone adventures, with classic treasure hunts in exotic locales (e.g. "The Son of the Sun", "Guardians of the Lost Library"), hilarious what-ifs with physics or magic (e.g. "On Stolen Time", "Cash Flow"), or yet another way for Donald to screw up a new job despite extraordinary talent (e.g. "The Master Landscapist", "Incident at McDuck Tower").
It's very sad to hear that Don Rosa is embittered and losing his eyesight. With all the enjoyment he's given millions of readers, he deserve a happier end to his career.