Charles Stross just wrote about some of the shibboleths in fantasy that drive him crazy. There are some things in a lot of fantasy writing that really break things for Stross, and he rightly attributes some of them to Dungeons and Dragons influence, but there are plenty of other reasons that fantasy writing ends up being bad.
I found it interesting to think about how some of the worldbuilding I did for Heroes By Trade looks in this regard. Stross was bitter about how currencies in fantasy worlds are so often fixed, based on simple base 10 conversions, and which bear no resemblance to the chaotic mess that real world currencies have always been. In the world of Heroes By Trade there are a lot of things that seem at first glance like they would be even worse than this in terms of violating immersion. There is an international standard for units of measurement, and the base unit is the meter. There are also languages strictly associated with fantasy races that are widely, nearly universally even, understood.
Both of those things I would consider unforgivable failures in worldbuilding if encountered on their own, but in the world I built they exist for a good reason. Systems of measurement were literally handed down by the god of Learning when that god created the satyrs, a race devoted to acquiring, sharing, and maintaining knowledge. Sure, a random upstart monarch could decide to start measuring things by their own units like feet or barrels or cubits but arbitrary measurements are hardly likely to take hold when a comprehensive system is already in place and the scholars of the world are all dedicated to maintaining it.
The prevalence of a Common language in DnD worlds has often frustrated me as it seemed so ridiculous. Spain and France didn't have a common language, much less Spain and China! And yet I am satisfied with having a Human language in my RPG. The difference there is that again, the language was handed down to the first humans by the god of Growth when they were created, and that creation was not so long ago. There is time for drift over the intervening couple of hundred years, but there are still going to be a lot of enough similarities that communication is possible. Again this is assisted by the fact that the scholars of the world are far more thorough and dedicated than the scholars of Earth ever were - they were literally born to do just that.
Thing is, I recognize the utility of a common language. It can be fun to have characters enter a new culture where they don't speak the native tongue, but sometimes it ends up being a real blockade to enjoyment. If you have a dozen games sessions that span a few weeks of world time the characters still can't speak the new language reasonably but people are probably tired of months of pantomime and guesswork and would like to just *talk* to somebody please! At some point roleplaying people who can't speak to each other gets boring and having a common language really cuts through that.
Personally I really like worlds that make sense. I have often found that DnD based worlds were utterly ridiculous, so unbelievable that they ruined the experience. I like magical worlds, but I want a world where there are some fundamentally different rules but then things make sense once you accept those different baselines. Sure, people can hurl fireballs and jump over walls, fine. But if so why is it that rulers still seem to think that fortifications and armies are useful when it is clear the only real threat is the super heroes running around who pretty much ignore such things?
I want to be able to list the impossible stuff about the world, then follow that where it leads. Most fantasy worlds list the impossible stuff, then continually make up new impossible stuff to justify why the world doesn't make any damn sense when the first list of impossible stuff is fully thought through.
Makes me wonder if Stross would buy into my worldbuilding or if he would find it as ridiculous as all the other things he rages about.
*** Also in Kickstarter news, my game Camp Nightmare has nearly all of the big ticket items bought up, so if you want to get your name or your creative ideas into Camp Nightmare then get on that! There are still tons of basic game buy ins left, certainly.