Whether or no the plot works for you, I certainly can't address. I can say it worked for me though.
But I really must object to the claim that the Destiny trilogy somehow lacks depth. It's full of thematic depth -- it's about how an entire society of people face their own impending mortality, and about what the meaning of life is in the face of its imminent, mass termination.
Now, I will say that that makes it ground that David Mack has tread before. Wildfire was essentially about that same theme, though on a much more personal level. Mack is brilliant at bringing existential angst into the Star Trek Universe -- a world that doesn't normally lend itself to that kind of pain. The difference between Wildfire and Destiny, though, is that Wildfire is much more personal -- and that while some survive, one of the central characters does not. Destiny, on the other hand, is about social death -- and social redemption.
I never really got that.
Course to me Star Trek is about two things.
Exploring space and starship combat.
Anything additional is just gravy.
But-- to get to the exploration- and why we explore, and for that matter, to go to war, you need everything else. I think you may be a bit like me sometimes- you watch Simpsons because its a cartoon, and funny, but miss the political and social commentary? (This is a theory/example) whereas my brother has a decade on me, and gets all that stuff, and is always beating his head against the desk that I don't get it- even though most of it happened before I was born...

Anyway- for the sake of our humanity- for what it
means to be human, we can't go blundering around the universe or blowing things up- as cool as those SFX are. The Federation defends itself- from death, but also things like the Dominion, who brought "peace" and "order" but at cost- freedom, and a bit of genocide...
Humans also explore to learn, better ourselves, help others, and those aspects can't be ignored- because if they were- we'd be ignoring them now... which, arguably, we are...
But the point is, if Trek was merely coming up with what could possibly be on other planets, and space battles, exclusively, the exploration would not cancel the war, and I think you'd find that without that morality, something would be lacking- especially in literature... most TV/movie stuff has already sunk.