Well, since the absolute best Ravenloft campaign I ever ran was based heavily on the Strahd/Tatyanna story and her cycle of reincarnation, I might quibble with that.
But you do raise an interesting point. I wonder how many of us who truly, deeply dislike this change are also the ones who consider the Ravenloft novels an important part of "our" canon. The novel I, Strahd is easily one of the best of the line, and is also the source of a lot of the deeper looks into Strahd's background and personality. It heavily influences my view of the character, and indeed Barovia as a whole. I can quite easily see how those who haven't read it might have a different view of the importance of specific details in his history.