I wouldn't necessarily say a complete change. What has changed is that many of the WWE Divas can now actually wrestle. Alicia Fox is pretty good inside the ring as is Gail Kim, Beth Phoenix, Tamina, Natalya & Michelle McCool. Jillian is someone that's really impressed me with how much she's improved. The match that she had on Superstars a month or two back with Gail Kim is probably the best women's match I've seen the entire year from either WWE or TNA. It wasn't a barn burner but compared to what we usually see out of the Divas on Raw or Smackdown, it was pretty close to epic. Eve Torres has also improved noticably as has Layla.
However, the Divas are primarily used as shit filler on both Raw & Smackdown. Usually, the only opportunity you'll have to see a good women's match in the WWE is, sometimes, during a ppv or on Superstars. It's a shame because most of the WWE Divas are actually pretty decent inside the ring.
At the same time, I think we also have to be realistic. I know that we love the idea of any company having a lot of depth and focus in every division, but it's just not going to happen with the Divas. As has been said numerous times in other threads like this, women's wrestling has never been a signifigant draw in the United States. That isn't something that people say only because Vince McMahon said or believes it, it's historical fact. All you have to do is look back through wrestling's past here in the states and it's clear that women's wrestling never has been and probably never will be a relevant force in the states. There have been various times in which the WWE has attempted to have a serious women's division but it's just never really caught on. They've had women wrestlers that've put on good matches, but the reaction has always been rather lukewarm. Even TNA has given up the idea of serious women's wrestling, and the Knockout Division used to be one of the best things about TNA.
For all intents and purposes, most internet fans would love to see the Divas become relevant in the WWE but I don't believe it's gonna happen because most other fans just don't care enough about women's wrestling for the WWE to make the effort. Aside from that, wrestling history is working against it.
Well then why have Divas wrestling at all? If they don't draw then cast them aside. Nothings going to be a draw if you don't give it a chance, and right now with the Divas as they are, they're certainly not being given a chance.
And for the record, Jillian is far better than someone that's "improved". She's a hugely decorated women's wrestler that has been buried in the WWE from day 1.