It's a little tough to explain without sounding glib, but the gist is that in my opinion the purpose of Star Trek, when functioning properly, is not just to be optimistic, but aspirational; it's to show us a vision of a future in which we've surmounted the problems that face us today.

TNG has so far been the keenest example of this, moreso than TOS or any of the Treks that followed. DS9 may be my favorite Trek, but it's also responsible for setting a dubious precedent of darkness in the property that I don't think subsequent showrunners have been capable of fully wielding, or even of fully understanding.

A major part of this, for me, is the nu-Trek focus on "optimism" over "aspiration." Yeah, it might sound like arguing semantics at first, but I really don't think it is. Regardless of the dictionary definition of those two words, we use them in specific ways in modern parlance.

I feel like most people understand optimism as a positive attitude, a glass-half-full outlook, or even just a sunny disposition. At best, it's understood as personal traits adhering to a broadness of vision, generosity, and kindness. Yeah, these are good and virtuous characteristics; but they're not really the same as something being aspirational.

A future we aspire to is a very different thing than a future containing positive people. There are positive, optimistic people all over the place in today's world, and yet... just look around. We kind of live in hell!

I guess what I'm saying is that optimism is mostly an emotion, whereas aspiration is a goal.

Star Trek, when functioning as it should, is aspirational because it shows us what humanity and society could be like once we surmount the problems facing us today.

So I guess that this, for me, is the principal failing of Abrams and Kurtzman-era Trek; in this future, humanity still succumbs to the pains and pitfalls of present-day life in a way that suggests we won't grow out of them. Sure, they contain positive, optimistic, kind, gentle, generous people, but society as a whole has simply iteratively progressed instead of having wholly transformed.

There are so many little specific cumulative examples I can give of this, but I know once I start listing them, I'll forget to list ten more that are better. Maybe I'll make that list someday when I have some time to kill; but for now, the biggest offenders are the constant tropes of The Galaxy Facing a Danger Unlike Anything We've Ever Seen, and the handling of Section 31 as an organization + subsequent reality of the movie.

Oh, and another major problem is that the seasons are all too short, so we rarely ever get any breathing room downtime with the characters! 20+ episode seasons are a vital, crucial, fundamental component of Trek as a property, and it's really not adapting well at all to the modern format of shows.

Long answer woops!!