I watched this episode today. I find there's a lot to talk about here, even though it seems like mostly a standalone episode. The arc stuff is all in the background, but it's there. As people commented in this thread ten years ago, there's the Delenn/Sheridan relationship building, there's Franklin using stims, Delenn sacrificing herself for a cause, Lennier following her, ...
This episode is another reminder that things don't necessarily end well in the B5 universe. There's so much tragedy here, but multiple viewings do blunt the shock somewhat. That empty seat for the Markab in the council in later episodes still gets to me, though. I also try to picture what it must be like for the few Markab left alive across the universe (side note, a disease that kills 100% of infected individuals seems a bit much? Surely there's going to be one or two miraculous survivors here and there?). I also vaguely wonder what would happen to them in terms of legal status.
As for the debate on whether the Markab were unified in their belief that the disease was a punishment, I tend to think not. But enough of them believing it would make a very bad situation worse, and could lead to exactly what happened here. Then again ...
There must be some REALLY extreme weather on the Markab homeworld, if the island where the disease first occurred was cut off from the rest of the planet for a whole year. I can see how that would have made it harder to research the disease, since everyone who had it would have been long dead. Still, the disease had been back for a year by the time it gets to Babylon 5. If Franklin could figure it out in a day (granted, he had a dead Pak Ma Ra to work with), you'd think Markab doctors would have been able to figure something out, even if they were all under orders to ignore it. I guess we don't know enough about Markab society to say.
Aside from all the tragedy, there's some really funny stuff in this episode. The ritual meal and the flarn conversations are pretty amusing. I still fairly regularly use the word "flarn" in conversation because it amuses me so.
I've also often wondered what Delenn saw in that temple. I used to think it was a real person, but it does sound more god-like, or vision-ish. I don't know.