I agree with most of what 's been said already, so just a quick thought.

While it is interesting that Londo is chosen, apparently for his willingness to sacrifice himself, I find it far more interesting that Delenn, who is being built up as quite a spiritual person and (despite recent revelations) good-guy type figure, is not.

In the light of later events, it is not all taht surprising, but it is another subtle piece of character building of the type we are subsequently led to (temporarily forget) - just for it all to resurface after the Shadow War.

ANd on a different subject - some fantastic Ivanova lines too - I particularly like the "just kiding about the god part" bit!