Elder Evils

I've always enjoyed the concept of the D&D book Elder Evils, even though it ended up being a little too surface for my tastes to actually be usable.  I didn't re-read it cover to cover; I skimmed around and read my favorite chapters.  The ones that especially stand out to me are as follows:

• Atropus.  This undead god/planet/thing reminds me a lot of Eox, from Pathfinder's Distant Worlds.  The two are a match made in... well, deep in some horrible Lovecraftian vision of outer space, maybe.  Because both are relatively light on detail, combining the two of them is a no-brainer; if nothing else, it gives a few more places to explore.  I do think that undead in D&D are too varied and most of the variants have too many minor, and in fact even insignificant details to separate them, and many of them are only undead by fiat, since they clearly aren't the reanimated corpse or spirit of anything.
• The Leviathan.  This makes me want to re-read Book of Fiends by Green Ronin, who had an archdevil named Leviathan, based on the Biblical figure of the same name.  The version used here is a bit more like the Midgard Serpent of Norse mythology.  Of course, either archetype is acceptable.  The actual scenario as spelled out here seems to be a bit too weak to really make good use of the archetype, in my opinion.  Then again, bizarre save the world plots are hard to pull off, even in a 1-20+ level D&D campaign. 
• Sertrous. This obyrith lord in the shape of a serpent is an odd one.  Not that the concept isn't good; a serpent demon lord and his yuan-ti cultists rising and needing to be faced down; but some of the details just don't really add up.  To wit: the demon lord is dead, but not exactly.  However, there are stats for an aspect of Sertrous that are exactly like that of an obyrith lord from Fiendish Codex I.  It's in the exact same CR range (22) and has the exact same type of stats and special abilities.  It seems clear that we're supposed to assume that the Fiendish Codex stats aren't actually correct; rather, the "Demonomicon of Iggwilv" stats in the Dragon Magazine series are supposed to be correct, which are more in the upper 20s to lower 30s for CR.  Given that the only way I'd be interested in using these guys is in an E6 game, I think the lower versions are appropriate, and Sertrous should just be considered an obyrith lord, not some odd dead demon lord trying to be resurrected.
• Zargon the Returner.  Another fiendish creature of some sort; hinted to be an ancient baatorian who kills gods and whatnot, the fact that the creature only has a CR of 16 seems... kinda odd.  Beside the backstory, the rest of this chapter is surprisingly light on detail and very cliche.  And given that the backstory is heavy on D&D specific esoterica... I'm nor sure how useful that one is either.

As I said; I'm not huge on "save the world from impending global apocalypse" scenarios, necessarily, but I am really big on campaigns that feature undead, fiends, or both—which really highlights my interest in the specific chapters that I most like.  I'm also not necessarily entirely sure what to do with powerful fiendish lords, princes or archfiends,  if they're not save the world requests, of course, so I've got some work to do to figure out how to think about how demonic plots and politics work with smaller potatoes.  One of my favorite ways to do so is to think about having the game actually set in the world of fiends in one way or another.  This is the approach I'm going to take with my FALLEN SONS campaign noodling... once I actually get around to doing it.  This ends up being an exotic intrigue and skulduggery campaign, though—with patrons who are powerful archfiends rather than human(oid) crime lords.

Whatever.  I don't have a problem with the so-called issue of humans in rubber suits.  It worked OK for Star Wars, and it works fine for D&D.