Reddit reviews The Fifty-Year Mission: The Next 25 Years: From The Next Generation to J. J. Abrams: The Complete, Uncensored, and Unauthorized Oral History of Star Trek

In my digging I found this book.

Quote (Originally by Terry Farrell, who played Jadzia Dax):

> “In my opinion, he’s just very misogynistic. He’d comment on your bra size not being voluptuous. His secretary had a 36C or something like that, and he would say something about “Well, you’re just, like, flat. Look at Christine over there. She has the perfect breasts right there.” That’s the kind of conversation he would have in front of you. I had to have fittings for Dax to have larger breasts. I think it was double-D or something. I went to see a woman who fits bras for women who need mastectomies; I had to have that fitting. And then I had to go into his office. Michael Piller didn’t care about those things, so he wasn’t there when you were having all of these crazy fittings with Rick Berman criticizing your hair or how big your breasts were or weren’t. That stuff was so intense, especially the first couple of years.

It's covered in the 2nd volume of "The Fifty-Year Mission":

https://www.amazon.com/Fifty-Year-Mission-Generation-Uncensored-Unauthorized/dp/1250089468/ref=sr_1_2?ie=UTF8&qid=1486751362&sr=8-2&keywords=the+fifty+year+mission

As for why, it's both of the things you mentioned. Farrell claims that Berman acted pretty skeevy towards her a lot of the time. No outright "sleep with me or your fired" but some things she found inappropriate over the years. Berman doesn't really comment on that part of it. Also, she wanted to do Dax as a reduced role during the seventh season, doing maybe half the episodes. Berman (Or, Paramount, as Berman claims) apparently wouldn't budge, insisting on full-time or no-time, and thought she'd buckle. She didn't buckle, so she left. Apparently this all happened without involving Ira Behr, who seems pretty pissed that the whole thing happened at all, but both management and Farrell chose not to involve him.

You would enjoy reading Mark Altman's & Ed Gross's books "The Fifty Year Mission", if you haven't already. It's broken up into two volumes, one for TOS & their movies, and the other for the 24th century voyagers.

https://www.amazon.com/Fifty-Year-Mission-Generation-Uncensored-Unauthorized/dp/1250089468

I'm currently reading The Fifty Year Mission: The Next 25 Years. The first part of it goes pretty well into the genesis and growth of TNG over it's seven year run. You might enjoy it and the first book as well.