It doesn't help much that they also didn't use change in the characters to convey developments and time on the ship. Voyager was mired in a serialized stagnation when its premise demanded at least a mixture like what is seen in earlier seasons of DS9 (which, go figure, felt like a different setting from the start to end of the show). When you look at contemporary discourses surrounding both shows, you'll notice that this was in fact a consequence of how older fans vocalized frustration with the "darker" and slower-paced storytelling on DS9, so it's understandable to see why the production took this route.

Star Trek is at its strongest when it excells even within budgetary and production limitations, so they could have still achieved this effect even with the ship models they started out with. Christ, how often do they do redresses on these sets anyway? Could have changed some panels and added different colored glowy bits to the gell packs if it's just a visual thing.