The Next Generation seasons and films
After the failure of Star Trek TOS on TV, but the success of the films, Gene Roddenberry decided to take another stab at doing Star Trek on TV. He knew that no network would pick up an original series resurrection, especially given the aging actors, but if he breathed fresh life into the Star Trek by bringing forward a new cast and (hey why not?) a new century, then Star Trek might finally be as much a commercial television hit as it was a critical one. Roddenberry was right. Star Trek TNG was the right balance in a number of ways. A lesser show would have simply ignored the long passage of time since TOS' cancellation and continued TOS from where it left off, painful 1960s aesthetics and all. Instead, TNG appealed to a new generation of space opera fans with a revitalized, fresh, modern Star Trek which respected the legacy of TOS while forging a new direction of its own in a new century.
TNG went far beyond revitalizing the cast and the setting though. TNG was a much deeper, more cerebral show than TOS. TNG had its fair share of duds like TOS did, but this time around there was a great deal less network meddling. Production quality also substantially improved, particularly in the later seasons. Even in TNG's relatively weak opening seasons there were a number of truly profound episodes. Both parts of the pilot Encounter at Farpoint of course along with Symbiosis, The Neutral Zone, The Measure of a Man, Q Who, and Peak Performance are all stellar examples. Now that Star Trek was finally given real freedom to think outside the old-fashioned cultural box that so plagued TOS, the second generation of space opera was truly born.
The second generation of space opera is generally thought to begin with Star Trek TNG because TNG was the first space opera show to feature production quality and storytelling structure that feels largely modern. Unlike TOS, TNG didn't feel overly tied to the historical era the show was produced in. It succeeded in imagining a future that looked much more believably futuristic than TOS. The production quality thus aged better than past science fiction productions. TNG also featured some light serialization in a handful of places, another staple of modern space opera. Serialization was most notably used with the development of Worf's character and the subsequent revelations about Klingon culture, adding valuable depth to this already popular alien civilization.
Star Trek TNG enjoyed enormous commercial and critical acclaim. Its cultural influence spread so far and wide that the show had a tremendous effect on the entire genre itself. A great many other space opera shows were made following its success, all of which were benchmarked by the standards set by TNG. Everything from the Stargate franchise, to Babylon 5, to Farscape, to TNG's two spinoffs Deep Space Nine and Voyager along with many other shows were all mostly replicas of the popular TNG formula.
With such great characters, great writing, and marvelous originality, Star Trek had finally paved its way to success. And successful it was. TNG ran for seven marvelous seasons and continued on long after that in the form of films, producing such classic episodes such as Déjà Q, The Best of Both Worlds, Family, Data's Day, Darmok, The Inner Light, Relics, and perhaps the best and most underrated episode of the series, Tapestry. Then like the first president of the United States, TNG knew it was time to voluntarily end its own critically acclaimed career after seven seasons with a marvelous finale, setting a precedent for all future Star Trek shows to come, rather than riding the wave until it simply fizzled out. Star Trek TNG certainly wasn't the best space opera show ever made, but it is certainly among the top contenders for such a title and left behind an historic legacy as well. A true classic.