To me, the show would have been more effective if:
1. They hadn't relied on alien crew members from species that had already been explored more effectively in the other series (Vulcans, Klingons, Borg etc.) - this detracted from the "far into the unknown" feel they seemed to want in the beginning - explore new alien concept (like Odo and the Jem'Hadar were on DS9)
2. The ship hadn't stayed in such perfect shape - I would have liked to have seen the crew actually have to abandon the Voyager at some point, and re-name an alien ship they acquired the "Voyager", or else have the ship get in terrible shape, and have to be retrofitted with parts from many alien cultures they encountered.
3. If a Maquis had ended up in command of the Voyager. It would have been interesting to see what would have happened if one of the Maquis, who was a former Starfleet officer, but no longer bound by its rules, ended up in command, with a real "by the book" Starfleet type acting as that captain's first officer - would have created some unique command decisions we might not have seen from Picard or Sisko, if the captain was no longer a member of Starfleet (e.g. "Prime Directive? What Prime Directive??"
4. Send the ship into an entirely different galaxy, not just a different section of our galaxy, the "delta quadrant" - a radically different galaxy where life is completely different - where the possibility of getting home seems even more remote and unreachable, so the crew has to struggle with the concept that they may have to create a new life for themselves, in a galaxy they cannot understand or predict - the rules of science don't always apply here ...
5. If they hadn't made the make-up of the one unique alien on the regular cast, Neelix, look so much like an Earth animal (according to one entry on Memory Alpha, Neelix's alien design, with its spots on the forehead and mane of hair, was meant to ressemble an Earth warthog, based on inspirations from the character in "the Lion King", but I'm not sure if that's true). I always find that on shows where aliens look like Earth animals (e.g. cats, dogs, bears, etc.), it makes the show feel much more like a cartoon or a kids show to me, rather than serious sci-fi ... Neelix was certainly cheery and bubbly enough to be a character on a children's TV show - move over Teletubbies and Barney the Purple Dinosaur - here comes Neelix, the friendly space warthog!
The instant he called Tuvok, "Mr. Vulcan" on the first episode, I almost abandoned ship! ;-)
(Heck, didn't Neelix actually get his own show on the ship in one episode, something like "Cooking with Neelix"? - Yikes!)
In my opinion, Voyager had the potential to be one of the most unique Treks ever made, but fell into some formulaic elements from the previous Treks that had worked for the earlier shows, but unfortunately gave this series too much of a "been there, done that" feel for a viewer like me (though it did have some well-written episodes...)