I don't think that the time between shows is a crucial thing, but rather the people behind the show. Let's face it, Berman and Braga were worn out. Had they bothered to hire fresh new minds from the start (like they did with Coto later on), certain season 1&2 episodes wouldn't feel like a rehash of Voyager.It really is a shame they wouldn't let them take a longer pause between series.
I've stumbled upon an old article (November 2004) on TrekToday, check this out:
(Ira Steven) Behr was invited by Star Trek: Enterprise executive producers Rick Berman and Brannon Braga to a meeting to give professional input on why the show was not achieving as well as previous Star Trek series, but he does not believe his contributions were incorporated into the show, which he has not watched since. "I'm sure that as soon as they left the meeting they stabbed my picture with a knife!" he joked. "From what I understand, Brannon assembled the writing staff the following day and said, 'You know what? We have a pretty damn good show here and it doesn't matter what people say! We're going to stay the course here.' Of course, I'm hearing this second or third hand." However, he said he and Berman remain on cordial terms socially.