Super. I just found this too:
"Deep Space was only a modest success during its original run, but its reputation has steadily grown over the last decade."
TNG is the only Star Trek show that became more popular during its initial run, but my observation is that DS9 is more popular now than it was in 1999. People who didn't watch Trek until recently tend to like DS9 most, and a lot of fans who didn't give DS9 a chance originally came back later and loved it.
It may be due to DS9's re watch-ability. Its style allowed characters to express themselves in a more interesting way. It was less restricted.
The subject matter was more gripping and cutting edge than the usual alien/plot of the week style.
I don't think it's a coincidence that in the age of Walking Dead, and Game of Thrones, fans find DS9 more interesting.
The same is arguably true about the 23rd and 24th centuries "in-universe." Kirk and Picard were just as prone to make mistakes and make errors in judgment, even if the show seldom called them on it. I don't want main characters clamouring for a return to Friday's Child or The Apple or A Private Little War.
The main characters would be acting against this trend pushing to return to 23rd and 24th century ideals.
This would keep the tone of the show optimistic and have a lot of modern cultural relevance. It would raise the question, can high minded principles really stand up to actual outside threat, or do they force us to retreat in fear and turn on each other? Can you have optimism without naivete?
Picard or Kirk would make makes mistakes, but because they were the hero character, the show would rarely acknowledge it. Or, despite the mistake, everything would always work out in the end anyway.
In today's shows, a hero character can actually do the right thing, and still pay for it, simply because they were naive of the people or circumstances they were dealing with.
In G.O.T, Ned Stark did the right thing and warned a dangerous queen that he was going to reveal her infidelity to her husband, the king.
So she would have enough time to flee to safety before the king takes revenge. She killed the king before he could be told, and Ned ended up being beheaded.
Later even the other good characters made note of how naive he was to even tell her, even though he was a good man.
But it made the story more complex and interesting to watch, than the simple black/white morality tale without considering other factors.