I generally like to post my initial thoughts without reading the comments, but halfway through now and there have been some good ones, and I was unaware of the ULG short story, so I will add a few thoughts.
The fact that this idea may have been taken from one of Ursula's short stories does not bother me. With the caveat I have not read it. Though I can certainly see how that knowledge could detract from one's enjoyment of the episode. This is Trek and sci-fi, just because an idea has been explored before or elsewhere does not mean it should be off-limits. Be it a perfect society built on a dark secret (This Side of Paradise, The Cloud Minders), the dehumanizing effects of downloading human consciousness into a computer/robot or AI governance (What are Little Girls Made Of?, Return of the Archons), or a society willing to make a terrible sacrifice to maintain tranquility (A Taste of Armaggedon).
As for this episode, I knew something was up when the pathetically inferior ship fired on Enterprise. Plus, when something seems too good to be true, it usually is (This Side of Paradise, The Cloud Minders).
As for the idea that this was a plot episode instead of a character episode, I am not sure I agree. The child is willing to meet his doom in service of the greater good (informed consent ir not). Pike is facing a similar dilemna. One that we know he completes the same way a child did.
Lastly, I think Alora's point is spot on, shining a light on our willingness to sacrifice our children to, say, gun violence, for essentially nothing. Beyond plot/character, this a is a great social commentary episode along the lines of "Let this be your last Battlefield."
It is not perfect, to be sure. The reasoning for why it is necessary is shallow, and Uhura seems unconcerned about boowing an inferior ship out of the sky. And the ending is dark (for those that dislike that).
But I like it more because of the ending. No fix this time. If I could go back, I think I'd be in 9/10 range. This is shaping up to be the best S1 since TOS (though PRO was awful good, as were the first half of Disco & Picard, and S1 of LD).
I'd also rate it as the top half-season of NuTrek.
Excellent:
SNW so far
Very Good:
DISCO: S2 first half, S1 first half, S4 finish
PIC: S1 first half, S2 start & end.
LD: almost the whole thing. Mariner did get tedious there for a bit, but the S2 finish was AWESOME.
PRO: Whole first half