I would take the opposite stance, I don't expect orcs in any setting, nor do I expect goblins, or dragons or anything. The entire point of creating a new setting, is that it is new and different from other settings. Saying that you have justify every creature missing that Tolkein used in his middle earth setting, or every creature that is in the Forgotten Realms, is a really strange take. I don't recall anyone crying because there were no orcs running around Ravenloft.
Ravenloft, much like Dark Sun, is by nature very, very different than the typical D&D setting. Plus there's always the option of having orcs brought in by the Mists (one example of how to run Ravenloft encounters from, I think, the first MC Appendix involved an ogre),
and Ravenloft was originally set up as a "weekend in Hell" and can still be run that way, thus allowing orc PCs,
and I've seen at least one homebrew domain that featured lots of orcs,
and 3x Ravenloft had caliban which specifically used orc stats.
So there's plenty of ways already in the game to allow for orc PCs. Whereas with Dragonlance, you
also have to bring in something like Spelljammer or Planescape (or at least planar travel) to allow for an orc, and both of those things then bring in other issues for the setting (how would a dragon fair against a spelljamming ship?).
If, however, you're planning on making a world that's basically the same as every other standard D&D world but mysteriously no orcs... a lot of people are going to want to know why. You can come up with explanations for it, even very good ones--but "because I don't want it to be just like Tolkien" is
not a very good explanation, especially if you
also use dwarfs, elves, and something very much like hobbits.
If Dragonlance races had been, I dunno, humans, rogue draconians or traag, minotaurs, irda, shadowpeople, and kender, then I doubt anybody would care one whit about orcs, because none of the PHB nonhuman races are included.
