I never understood the logic people place on comparing real ranking systems in Earth military's and Starfleet's version of it. It's set centuries in the future, and is a amalgamation of ranking systems from different alien cultures. So for me the comparison is flawed.
Having said that, I think the timing was just right. In terms of story telling, viewers put a lot of weight behind the 'captain' rank. In the episode itself, the way the story is told, gives us the feeling that things are getting way more serious and dangerous. Giving Sisko the rank of captain, which means a lot to fans, adds to the gravity of it.
AKA, shit is getting real.
Having said that, I think the timing was just right. In terms of story telling, viewers put a lot of weight behind the 'captain' rank. In the episode itself, the way the story is told, gives us the feeling that things are getting way more serious and dangerous. Giving Sisko the rank of captain, which means a lot to fans, adds to the gravity of it.
AKA, shit is getting real.