I believe that a dramatic visual style would have helped the show --- let's say something that looked like a Flash Gordon serial, done to HDTV standards --- at least in making it look original and energetic, and maybe even adding a bit of whimsy to the production. (Trek has never been good at whimsy.)
But there's no way that it would have made the show a hit. The worst problem Enterprise had was starting out with stories that were too often wheezy and tired --- good grief, they did a holodeck episode their first season (with another holodeck cameo that season!) --- that were just too out of synch with what audiences were looking for.
Not to mention that ST was never meant to be retro. It was supposed to be cutting-edge and forward-looking.
Is that the episode some have either tried or did have removed from official canon because it screwed everything up so bad?
The one where Janeway and Paris turn into slugs?
First off, "official canon" is essentially a myth. There's no office that goes around sticking "canon" labels on things. "Canon" is a term coined by fandom to refer to the original source material of a franchise as distinct from derivative works and pastiches. The people making a TV or movie series never give any thought to whether it's canon, because that's more a consideration of fans and critics, and because whatever the showrunners create is the canon by definition. The only times creators/studios really address the question of canon is when they're discussing tie-ins created by others and whether they would be acknowledged by the canon.
So the makers of the shows themselves just think in terms of what they choose to count as really having happened. Sometimes writers make mistakes and want to erase or gloss over them. Writing is a process of constant trial and error and editing and refinement. But in serial fiction, they don't have the option to go back and cut out their mistakes, since they're already out before the public; so they have to gloss over their mistakes by retconning them, just pretending they didn't happen. They don't have to try to get a ruling from somebody to get it "officially" removed, since the only people who decide what's "real" in the universe are the people telling the stories. So yes, Brannon Braga and Rick Berman are embarrassed enough by "Threshold" that they both decided it basically never happened.
It was removed simply by being ignored.
Oh, and they turned into salamanders, not slugs.