Voyager had a lot of wasted potential, I think. It had a few really well thought out and developed characters (The Doctor, Seven, Kes, Seska, Tuvok and Neelix), leaving everyone else completely flat and undeveloped (Harry Kim, in particular.) And Janeway could've been so much more.
Even then Seska and Kes didn't stick around. I definitely think bringing in Seven at Kes' expense for the sake of 'sex appeal' was a bad idea. Seven's character didn't even really need sex appeal, her story was compelling enough. I always thought Jennifer Lien was the most attractive anyway, personally, so that move never made much sense to me on any level.