I think the Federation almost coming to an end multiple times in the past 30 plus years was a bit of a wake up call. Starfleet weren't ready for the Borg, they weren't ready for the Dominion, they weren't ready for a synthetic revolt. Starfleet and by extension the Federation had been complacent and that complacency has resulted in a lot of death. It would be understandable that the Federation would become hawkish, isolationist and resistant to aiding a people who have actively plotted to destroy the Federation since it's inception.
I agree completely and again these are elements I would love to see explored. What are the limits of the kind of 'open society' implied by what we have understood to be the Federation? What are the factors that cause civilizations to rise and fall and can sentient beings short circuit these cycles intentionally given enough personal, social and technological evolution.
Star Trek gave us a humanity that had apparently thrown off its baser instincts - how does that really work? Does it have permanence? These are the types of things that interest me. I guess I was hoping that a 'mature' or more 'adult' take on trek was more than season long story arcs involving end of the galaxy scale mystery boxes, sex and cursing.