SHARK said:
I tend to think that such exclusion of such themes can be limiting, but then again, I'm not uncomfortable with such themes.
In classical literature, from the Trojan War, to the Greek Tragedies, through the Arthurian stories, as well as theological literature such as that found in the Bible, such themes are literally everywhere, and serve to not only teach lessons about the nature of humanity, but also to make for more interesting and dramatic stories.
It isn't really a question of whether they exist in the campaign or the world--these things *always* exist--but of how the story addresses them. Slavery, racism, insanity and other "mature" themes exist in Star Wars, LotR, the Homeric Epics and Vergil, etc., but they are not addressed in the kind of way that is potentially offensive to people (i.e. in a way entirely skill deficient)
Simply as a reply to your feeling that a campaign that doesn't incorporate these things might feel cartooney or limited, I have to disagree, citing as evidence what was until recently widely held to be the pinnacle of artistic achievement: the epic (art and it's derivative words no longer have any meaning, let alone a pinnacle). Yes, there is war in Homer and Vergil and Star Wars (I didn't want to say "Homer and Vergil and Lucas"; that would sure be inflating his achievements), and reference to human sacrifice (Iphigenia) and rape (Cassandra, both by Apollo and Agamemnon) and suicide (Dido) and slavery (again Cassandra, and Wookies, for that matter) and racism (fairly large in Star Wars), but these are heroic works and all of these things are absolutely cursory to the story except when they have some kind of negative moral force (like Iphigenia's sacrifice), in which cases how wrong they were is also central to the story.
Having said that, most of the ridiculous staples of D&D Fantasy have no place in an epic campaign either. Your game sounds really interesting SHARK, and if I or anyone else were going to explore "mature" themes (oi that seems an odd designation for them) we would probably be best served playing in a game like yours, and frankly that sounds a lot better than the average D&D campaign, which ignores a few and incorporates a few and generally just skips over most. However, if it is possible for a campaign to be as epic as a true epic, then I have a hard time believing that such a campaign would be anything less than equal to a campaign that perfectly explores less savory issues, which I doubt exists. Epic doesn't gloss over the tough stuff, it stares right through it.
In fact I think a truely epic campaign would be far more difficult to run than any other kind, but that's a book length discussion we won't get into.
*Oh how I hate following messageboard rules when somebody is so wrong you have the urge to smack them* (absolutely unrelated to the rest of this post and not aimed at SHARK).