I think Beanie is very good casting. While of course the actress playing Fanny needs acting, singing and comedy chops, what she needs most of all is a big, quirky and endearing personality. I think that all those other ladies are super talented, but when I think of them I think of their straight talents, not their big personalities.
The personality of the Fanny is more important than it is for Rose or Dolly in my opinion, because Gypsy and Dolly are better written and more compelling shows. If you can take your eyes off Fanny, you don't have much of a reason to see the show. (In fairness, I have never seen FG on stage, although I've read it, devoured the album, heard from people who saw the original production, read reviews, and seen the movie than a few times).