A big one would be to keep Ron Moore on the production team (and get rid of Braga). He had some great ideas for the show, but they clashed with Braga's ideas. With Moore, the show would have become more realistic, more gritty and more dirty.
I think you're mis-blaming here. For what it's worth, Braga wanted to do a season-long "Year of Hell" arc rather than just a two-parter. And need I point out that Moore & Braga were writing partners for years? Hell, they wrote two of the
Next Gen movies together.
Besides, Braga was only the showrunner of
Voyager in the fifth and sixth seasons. For the first season the showrunners were Michael Piller and Jeri Taylor; for the second, third and fourth seasons it was Jeri Taylor only; and for the seventh season the showrunner was Kenneth Biller.
Remember that
Voyager was under a
lot of pressure from UPN. It was the "flagship show" of the series, remember, while
Deep Space Nine was always second-tier in importance --
and it was attached to the network rather than being in first-run syndication like
The Next Generation and
Deep Space Nine were. UPN wanted
Voyager to replicate the success of
The Next Generation -- and they did that by forcing
Voyager to be as much like
The Next Generation as possible, including the episodic format and lack of character growth. And the writers on
Voyager accommodated that. (
Deep Space Nine was able to branch out a lot more precisely because
Voyager was getting all the attention from the execs.)
To make
Voyager a better show, firstly you have to make another show the "flagship series" so that
Voyager can branch out the way
Deep Space Nine did in OTL. Unfortunately, that means that
Deep Space Nine cannot coexist with a good
Voyager: you need to replace it with something else (sorry, but
DS9 isn't "flagship" material).
Personally, I think the best bet is
Star Trek: Excelsior -- make
Next Gen end after six seasons rather than seven, and have
Excelsior begin in September 1993 (less than two years after the release of
Star Trek VI: The Undiscovered Country). Let
Excelsior become the "flagship series" which UPN pins its hopes and dreams on, while
Voyager becomes the second-tier show that's allowed to take more risks.
You know how shows are typically broadcast with their seasons split in two, with a long gap between shows that usually goes from mid-November to mid-January?
Excelsior can begin on UPN in January 1995 with a big two-hour "event" show (think
DS9's "The Way of the Warrior") that comes halfway through its second season.
Voyager can then premiere a few days later.
Something else they could do is set up the story of the Maquis in the
Next Generation movie, which should come out on schedule in mid-to-late 1994.
Voyager can then follow on from the movie, in a way.