Part of what's so great about this episode is that it humanises the Jem'Hadar in a way that past episodes focusing on them failed to do. It did so not by having the Jem'Hadar rebel, as in Hippocratic Oath or To the Death, but by having them strictly adhere to the order of things. They die not because they dared to believe in freedom, but because they dared not to. They rejected the choice to have a choice, and consequently marched stoically toward their own suicide. Just like the Kira story, there's some really meaty material here to chew over, and this is probably the best Jem'Hadar episode of the entire series.
Agreed. I think the writers realized here that we needed to get a sense of who the Jem'Hadar are when they accept their role in the Dominion's plan, as the majority clearly do. More than simply humanizing the Jem'Hadar, it also helps cement our understanding of the Dominion and the threat they pose during this war. We might sympathize with the Jem'Hadar, but if previous episodes like the two you mention gave the impression that "freeing the Jem'Hadar from exploitation" would be a possible solution, this episode shoots the idea down, in a way makes the Jemmies less able to relate to the heroes even as it makes them more relatable. That's pretty complex writing, and serves to up the stakes as well as let us invest in the Dominion emotionally. Pointing out that Jem'Hadar are exploited gets you nowhere - they already know it, and accept it as their purpose. We're in the uncomfortable position of seeing them find dignity in it, preferring the comfort of their intended purpose to any attempt at freeing themselves. That's what makes this plot work so effectively; the regret that the most relatable and honourable traits in the Jem'Hadar are those that make them harder
to reach out to, rather than easier. It's really a tragic situation, and it's impressive how much more three dimensional this single episode makes the Dominion.
I suppose the Kira plot also works very well alongside it, showing how Kira herself almost slips into an arguably similar mindset. Her purpose is to keep Bajor safe, keep the peace under their treaty with the Dominion...and she finds that she's been led into working within the Dominion's plan with the best of intentions, almost, as you say, becoming the sort of person she always fought against, almost justifying that mindset to herself. Overall, I think the episode works because it makes the Dominion a more complex threat; not just a force of military ships and soldiers but the sort of power that can eclipse freedoms in other, more subtle ways. We begin to truly get a sense that the Dominion is a functional empire that truly could subsume the alpha quadrant.