[QUOTE="we saw Sisko switch back to the TNG-style when he was briefly reassigned back to Earth, and also a few background extras using them in "Rapture"[/QUOTE]
Looking from both a production and in universe standpoint VOY should have used TNG uniforms:
I can recall an interview about planning for DS9 and remember someone stating that new uniforms would be put in place so the viewer knew they were watching a different show (way to treat your audience with contempt!).
The in universe explanation for this would be that DS9 was not an official Starfleet station it was Bajor's station all the way through, Kira's (false) protest about Sisko not vacating at the end of season 5 supports this, therefore they wore non standard Starfleet uniforms being their at Bajor's request operating the station, that everyone including the main cast (Sisko, Bashir, Dax) arrive in TNG universe supports this, as noted Sisko reverts to his TNG uniform when he visits Earth in S4 and both he and O'brien change uniform when boarding the Enterprise in Emissary. Also everyone that I recall visiting the station wears TNG uniforms; Cal Hutchinson, Captain of the USS Odyssey (bridge crew also shown in TNG uniform), Bashir's academy nemesis and Worf both when he arrives on station and throughout Way of the Warrior. Everyone seen in the Homefront 2-parter wore TNG uniforms even the USS Lakota crew, surely not everyone on Earth was under Layton's command or uniform requirements.
Then along comes Voyager and the previous production statement of requiring a different look so the audience isn't "confused" gets overlooked, they even launch the ship from DS9 where it might have helped making the VOY crew stand out. Although Starfleet is barely shown throughout the show they seeming retcon the DS9 uniforms into all Starfleet use as they were worn by the USS Equinox crew and the staff at Utopia Planitia prior to the ships launch.
Generations unfortunately makes ZERO sense. scrapping the new uniform design at short notice seems to have left them short handed for the larger filming schedule. Looking at how the movie played out
- After jumping out of the period sailing attire Riker, Worf and Bev beam over in TNG uniforms with a handful of flunkies who are is DS9 uniforms. On the ship the rest of the senior staff opt for TNG uniforms.
- Returning to the Enterprise Riker switches to DS9 uniform while Worf hasn't changed
- Before beaming to the station Data makes a change to DS9 style while Geordi is unchanged.
- Between the Klingon ship arriving and trying to figure out what's going on by speaking with Guinan Picard swaps uniforms.
- Returning to the trashed Enterprise Picard switches back to TNG uniform
The entire thing in GEN was unfortunately very sloppy