I just meant that when people say what Star Trek is about, they need to say it's about space ships and time travel and little morality lessons. It's not just a space opera.
I disagree.
If I had to sum up what Star Trek was about, I certainly wouldn't mention time travel or morality lessons. Sure, they're in there... But it isn't a key feature of every episode. Even taken on average, it isn't a key feature.
The morality lessons aren't any more or less common than any other program on TV. It isn't like Star Trek is some sci-fi retelling of Aesop's Fables.
And the time travel is really just used as a plot device. It doesn't have to be in there. They could tell most of the stories without time travel.
"Space Opera" is generally understood to be "random adventures in space" - which I think describes Star Trek quite well. It really isn't much different from Buck Rogers or Space 1999 or any of the other space operas. Sure, maybe the average plotline in Star Trek is a little more substantial... But it is still space opera.
And, honestly, I'm not even sure that I'd say Dr. Who is
about time travel. It certainly features heavily into the character's background... And it is a feature of most of the episodes... But it isn't really the driving force behind the series. Dr. Who is, once again, largely about random adventures.
If you wanted a show that was genuinely
about time travel... Where every episode revolved around traveling to a new time and affecting history as we know it... I'd suggest Quantum Leap as a good choice.