Regarding DS9, if you are going to watch it, skip the first two seasons entirely. Basically, the point at which they introduce Elam Garrek is when the show gets good. TNG really had nothing but shit prior to season three, also, honestly. Voyager had some pretty shitty characters in it and the writing was so inconsistent that the likable characters wavered back and forth between interesting and want to see them die extremes. They also overused 7 of 9, with the show essentially becoming Star Trek: Look at the size of Jeri Ryan's Rack from the moment she was introduced, onward. That said, the interactions between her and the doctor were among the better parts of the later seasons of that show and there were a few really good episodes tucked into the ocean of shit.