Indeed - and as you say even TOS wasn't doing anything truly radical, only radical for prime time network tv.
Well, being "radical" and "being intelligent" aren't really the same thing. Popular entertainment is generally not the place to go, obviously, to really be challenged intellectually (unless you are talking about understanding how it functions from an analytical point of view, which is as challenging as understanding any complex social phenomenon).
I think, a lot of the time, when fans talk about Star Trek being "intelligent," what they are really saying is: it is a fictional universe that tends to capture the imagination of some intelligent people, or, alternately, "it appeals to their intellect." It's nerd fantasy fulfillment, in a lot of ways, and I don't mean that in a pejorative way, or at least not only.
Part of that is the "exploration" aspect, I think. Conceptually, it's a franchise that's built around the discovery of new worlds, civilizations, etc., for example, rather than just beating the bad guy, or whatever. That's appealing to the intellect, even if, concretely, what you end up "exploring" isn't really all that compelling at the end of the day, or new, or radical. Sometimes it is comically *not* new or interesting, but the *idea* of exploring "the final frontier" is still really compelling *as an idea*.
Often watching old TOS episodes cracks me up because the "alien" planet is about the most non-alien looking place imaginable. But the idea is still fun.
Also, a lot of times "intelligent" in this type of blockbuster really means something like "not egregiously or insultingly stupid," which is certainly a positive. I do my serious thinking during the day at work, but that doesn't mean I want my entertainment to take a crap in my brain, so to speak. At least not always.
Anyway, this movie was fine from that point of view, as far as I'm concerned.
I wouldn't mind a future movie focusing a bit more on the exploration angle, though I recognize that structure probably fits the tv format better.