Voyager was one of the cornerstone shows on parent network CBS, which was still new at the time and promoted Voyager heavily as part of their line up. This meant that even though the producers' impulse was to make a show for existing Trek fans that was more of the same, they were almost certainly guaranteed a yearly renewal until their crew's contracts expired if they threw casual watchers a bone now and then with hot ladies, punch-ups, and the odd episode that cashed in on popular culture trends. DS9 launched a few years too early to be a tentpole show like Voyager was, but it still wasn't immune to this kind of thing, hence Major Kira dressing in high heels and catsuits for a while, though the nickname "Pussy Bajor" sadly never caught on.
That's the reason for the boobs, the lack of better writing is ascribed by ex-crew like Bryan Fuller to the producers just being risk-averse.