One lovely thing about "Signs and Portents," which you picked up on,
is something I like to play with; implying one thing while saying the
opposite. Look at all the shadow's main representative, Morden, does: he
asks people what they want; he gets tossed out of Delenn's quarters; he
is pleasant in his demeanor at all times, never yells, always smiles, and
is courteous; he takes an action which saves one of our main characters,
Londo, from disgrace and resignation, and helps in the process of scragging
the bad guys in the episode.
And yet everyone walks away thinking that the shadows are bad. Which
was of course the intent...by the way in which they did "good."
Kosh prevents humanity from achieving immortality, scares the hell out
of Talia, never gives anyone a straight answer, doesn't seem to mind it if
people fear him...and we walk away with the presumption that he is good,
by virtue of the way in which he did things that were "bad."
In "The Quality of Mercy," I play a similar subtle game; the first
time you hear about the alien device, you're told that it takes the life
force from one person, killing them in the process, and gives it to
someone suffering a terminal disease to restore them. And everybody goes
"yuck, that's awful." But that is *exactly* what happens at the end, and
the general reaction is, "That's good."
This is something I do a lot in my scripts, which I don't generally
see a lot of other people doing. You *really* have to construct the
script very carefully to pull something like this off...a little game
between me and the audience.