Well when your overarching story is, "what say we fly home?" it's a bit difficult to make it good. Especially when the entire premise involves doing away with recurring enemies and cool alien races. Which is probably why they tried to shoe horn the Borg in so often.
Too bad that just made the Borg look like wimps when you have Voyager regularly encountering them and not being assimilated despite this being the race that destroyed a fleet, assimilated Picard, and traveled back in time to assimilate Earth, with the crew of the Enterprise only succeeding in beating them by the skin of their teeth each time.
And they also undercut the potential Voyager had by having them get into some battle with aliens every week only to be fully repaired the next. Paying lip service to the lack of resources and support, and their small number of crewmen here and there but never really having it matter. Focusing almost entirely on the main cast when they had a great platform to have recurring junior officers doing some interesting things, or even killing main cast members and having former recurring characters need to step up and grow. My point being, they had an interesting premise, but then basically ignored the potential it had in favour of using it to just introduce new alien races with a slightly different nose or forehead every week.
Anyway, going to have to disagree with TOS being the best personally. Don't get me wrong; it's great, has some great characters, and did some things that were utterly amazing, especially for the time. But TNG was better overall. In fact, the first two seasons of TNG are the worst seasons for that show, and they were the most like TOS. Read into that what you will.