The optimism is what makes Star Trek unique. It's the first futurist sci fi where things are unequivocally better. Not perfect, but considerably better on almost everything from now.
I'm sure they exist, but I cannot name another futurist sci-fi story, movie or TV show, where the future of the world is not experiencing or recovering from a nuclear war, cataclysmic environmental disaster, massive alien invasion, or global oppressive government.
There is nothing wrong with stories about a dark future. I like
Riddick, I like
Hunger Games, I like
Titan AE, I like
Firefly. I even like
Waterworld and
The Postman.
If you want to make a story about a future wracked by poverty, drug addiction, totalitarianism, natural disasters, and bigotry, that's fine. But don't slap the Star Trek insignia on it.
Looking at the recent direction of Star Wars, Terminator, Last of Us, Ghostbusters and others. If people want to create a sci-fi or fantasy story glorifying strong women, they don't need to override an existing franchise (and belittle the previous fan favorites).
The commercial success of
Kill Bill, the
Hunger Games,
Underworld, Resident Evil, Blood Rayne, and
Alita Battle Angel show that audiences will appreciate strong female protagonists if presented properly.