The kitchen sink aspect of things is one of the most misunderstood aspects of Eberron. The quote so often taken out of context is "If it exists in D&D, it
has a place in Eberron." Not "it exists in Eberron"... but rather, there's a place for it if you want there to be. More often than not, this is accomplished through one of three things:
- Xen'drik, the Dark-Continent-Meets-Atlantis. An unexplored continent twisted by magic, it's the perfect place to stick a never-before-seen-civilization-of-whatever-you-want.
- Khyber, the underdark. Following the pulpy feeling, this again gives you the opportunity for the Vril, the Lost World, Agharta, etc. Derro have no official place in Eberron. I have no plans to use derro in my game. But if I WANTED to, PCs stumbling onto a lost city of Derro in Khyber fits the setting perfectly.
- The Mourning, the bizarre-magical-cataclysm-that-warped-an-entire-country. Any monster could emerge from this bizarre event.
So, *I* prefer to focus on few races and few monsters and build up the cultures of each. As it stands, Eberron doesn't have wood elves, wild elves, purple elves, etc. It has the Valenar, the Aereni, the Qabalrin, the Gyrderi... all of whom are genetically elves with very different cultures. Want to use wood elves? Make 'em a weird tribe in Xen'drik. But *I'm* not going to use them. Likewise, you like abeil? Make them a culture in Xen'drik that's only just been discovered. Say that the Mourning transformed a human city into an abeil hive and now they're spreading like wildfire. There's a PLACE for abeil in Eberron...
but only if you want to take advantage of it.
So, I certainly sympathize with the "I hate everything being crammed into one world" syndrome. But the point is that Eberron makes it easy TO include what you want from any D&D book... not that it's all automatically there by default. Me? I leave a lot of it out!