I think Andy really likes them to work for that title. Look at Danielle and Camille, they've been "friends" of the housewives for a while now. Both deserve to be upgraded.
I'm not sure Jill Zarin would return unless she's given that official "housewife" tag from the off, we all know she's desperate but not that desperate. Personally, I think it would be weird having her back but I'm by no means against it. As
@cassiejojo said, there's a lot going on in her life and I for one would be interested in seeing how things have developed. She's still hugely popular and will always be the wicked witch of the
upper east
side. I would imagine Bethenny may be standing in the way to.
While I love the current cast, I think this will be the final season of these women all together. Especially with it being three years now. Really I could only see Tinsley getting the chop (unless she has a great season). Ramona and Luann will never leave, Dorinda and Sonja are firm fan favourites. Bethenny is the only one I can see walking away. Guess time will tell and I'd like some new blood to mix with the current crop.