Enterprise seasons
Star Trek Enterprise was the fifth Star Trek series, but set earliest in Star Trek's chronology, about 100 years before TOS. The show was conceived as executive producers Rick Berman's and Brannon Braga's attempt to course-correct the Star Trek franchise after Star Trek Voyager's popularity faded. They thought that taking Star Trek in a new direction, specifically out of the 24th century, would breathe new life into the series. There was nothing wrong with that rationale, but once again there were issues with the execution. As a prequel, there was a lot riding on Enterprise in terms of expectations from the fans. One need only look at the Star Wars prequels to see how difficult it is to meet such expectations. In terms of how Enterprise met those expectations, it was on par with the Star Wars prequels: better than people give it credit for, but nevertheless had serious flaws. From what we know of Earth history in Star Trek, the Earth-Romulan war was to take place during the time period Enterprise was set in. The assumption was that Enterprise would deal heavily with this.
Instead, what we got was a confusing plot arc concerning a "temporal cold war" being fought across time itself. Episodes not dealing with the temporal cold war were simple exploration, in the TNG-style formula. The formulaic exploration was easily forgiven, seeing as how Enterprise was Earth's first warp 5 ship, but it went on a bit too long. More importantly, the temporal cold war arc was entirely superfluous and extremely frustrating for fans. It wasn't until season 2 that the Romulans were finally properly introduced, and after that we didn't see them again until season 4, with season 3 being a DS9-style war arc featuring the temporal cold war and the Xindi, an entirely new alien threat. Season 3's Xindi/temporal cold war arc was some good fun to watch, but entirely the wrong plot arc for the show to be focusing on. So three seasons went by and ratings crashed. The show had systematically squandered its time and alienated its fan base.
Season 4 marked the end of the temporal cold war arc and the beginning of the buildup to the Earth-Romulan war, but the show had already been on borrowed time since season 3, having barely withstood some cancellation threats already. Having alienated so many fans in Enterprise's early seasons with the temporal cold war and filler episodes, the amazingly awesome fourth season was too little, too late. The show was canceled at the end of its fourth season, having never gotten its chance to depict the Earth-Romulan war. It's remarkable how well Enterprise's demise parallels Farscape's. Similarly, Farscape wasted a great deal of its time and lost significant viewers during its first two seasons, then in the third and fourth seasons finally became something special, too late in the game.
So Enterprise was an even bigger failure than Voyager. At least Voyager was a successful formulaic second generation space opera show about exploration. Enterprise failed at both the formulaic storytelling as well as serialized storytelling. But despite Enterprise having become a sort of black sheep of the Star Treks, it managed to produce some truly great episodes once in a while, reaffirming that it was, in fact, still Star Trek. Episodes like Minefield, Cogenitor, Twilight, Similitude, most of season 4, and perhaps the best and most underrated episode of the series, Vox Sola make the show well worth watching. While Enterprise's cast was not as strong as other Star Trek shows, characters like Archer, Trip, and Reed were a lot of fun to watch. The show did well at portraying humble characters in humble circumstances and while Enterprise generally ranks below DS9 and Voyager in terms of quality, it is still stronger than TOS and much of TNG.
After Enterprise's failure, the Star Trek franchise was down for the count for a while, so it's popular among Star Trek fans to hate it. This sentiment is understandable, but a bit myopic. With better writing, Enterprise could have easily given us a war story better than DS9's and exploration stories better than TNG's and Voyager's. Again, like Voyager, the idea behind the show was solid. It was just a highly neglected show by its showrunners Rick Berman and Brannon Braga. It's amazing how much episode quality shot up when Manny Coto signed on as the main showrunner for season 4. Contrast that work to the series finale, the worst of any Star Trek, which was written by Rick Berman and Brannon Braga. Any number of negative emotions could describe the resulting state of the Star Trek fan base after Enterprise ended. An 18 year straight run of uninterrupted Star Trek had come to a disappointing close. For the first time in Star Trek history, many fans were calling for the franchise not to be revived at all for fear of the demonstrated drop in quality persisting. But for all the painful background production drama, Enterprise nevertheless holds up quite well today as a well-written, well-produced, highly entertaining addition to the Star Trek chronology, especially if its unmet, perhaps overly high expectations are set aside and the show is evaluated on its own merits rather than how it compares to the rest of Star Trek. When viewed that way, Enterprise is fun and well worth watching. And perhaps most notably, Enterprise is arguably the first series any new Star Trek fan should watch now, since it takes place earliest in Star Trek's chronology.