I think going back early in season 6 would have worked. It gives two seasons(4 and 5) to flesh out 7 and we get some good Delta Quadrant stories that would not work in the Alpha Quadrant like Year of Hell and Equinox to name just two. I feel the writing was more tired in season 6 and 7. They needed a change imo. I still enjoyed the show but in hindsight it could have used a push in slightly different direction.
Equinox itself should've been something that happened in Season 1 or 2, not Season 6. Year of Hell maybe in Season 3, for half the season (the whole season really is just too damn long).
In fact, Voyager's whole premise and set-up doesn't lend itself to the usual 22 episode season model. It should've had a 10 or 13 episode thing, easier to keep the arcs and writing tighter. And the cast should've been smaller too, the Primary Cast should've been Janeway, Chakotay, Tuvok, The Doctor and maybe Paris. Everyone else would in the Secondary Recurring cast who didn't need to be in every episode.
I would have liked them to get home with maybe six episodes to go then had a couple 'homecoming/readjusting' episodes before they're called to use their DQ intel to fight off the Borg or something. Or could have done the full circle thing like TNG and DS9 and had some third Caretaker involved.
The 8472 aliens would've been a good series long plot point, with it being the Equinox crew who started the mess and then the Borg make it worse later. But then it ultimately would be revealed that the Female Caretaker was really behind everything including the Equinox crew contacting the 8472 aliens. She's the final villain that has to be beaten in the end.