Seven's clothing was uncomfortable, yes, but she had a good idea what would be expected of her when she signed the contract. It shouldn't be "poor Jeri" for simply living up to her part of the bargain. Plus, there were plenty of actors who had it worse. Her prosthetics were fairly tame when compared to what the Klingon actors had to go through, or what Ethan Phillips did, as Neelix. I heard a story at the Tulsa con where Tim Hagan (KM's hubby) was sitting with Phillips while he went through the two or three hour makeup ordeal. When Tim sympathized with him about it, Ethan replied, "I'd let them smear sh*t on my face for what they're paying me." I never heard of Jeri complaining about her costume or makeup.
Of the rivalries on the cast, I think Jeri's arrival was about the worst case scenario for an ensemble cast. Her character definitely changed the focus of the show, and many characters were overlooked in favor of her development (and the EMH's, to be fair). She also replaced a young actress that they others felt close to; it must have been tough. They managed to do some decent work, even so, and in the passage of years, I think most of that has faded away. I read a report about the NJ Creation Con where Kate admitted she might have gone overboard and apologized for it. When you listen to them talk about their time together at cons, it sounds like this cast had the most fun of any when it came to working together, and, like other casts, they have remained fairly close. That's something for a bunch of actors!