Making a Tolkien-like history for a game can be self-indulgent if you let it get in the way of the game. Making it for written stories is something else entirely.
Stories require some kind of setting. J. R. R. Tolkien made his history and setting as a place for his linguistic efforts. But it worked pretty well for his stories! Was that much detail necessary even for the stories? I doubt it. I suppose what matters is whether you're designing a game, or making a framework for a GM to tell stories to players, two quite different endeavors.
There’s an element of self-indulgence in writing about the long-ago, which can be bad for tactical role-playing games like Dungeons & Dragons. The writer wants to share what he/she has in mind even though that doesn’t make sense for the game. It’s a little like films: when you have a writer who’s also the director you can get something that’s very good (Guardians of the Galaxy or Avengers) or via self-indulgence, that’s awful (many movies most of us never heard of).
There are game masters who see their campaign worlds as creative frameworks, and that’s fine, but expectations should be low that the world will become more popular than just that, an exercise in creativity (in much the same way Tolkien, as per his quote above, originally created his world for his language skills). If you're planning to publish your campaign so that others can use it, the detail can be helpful to future game masters. But for the most part, from a game design perspective, much of the lore and language probably won't come up in actual play.
Yes, the Silmarilion does this; but that’s a compendium of bits left by Professor Tolkien, not a work he finished. You want to make a finished game, don’t you? Moreover, it wasn’t written for gaming. (Reading the Silmarillion is often like reading the Old Testament of the Bible.)
In other words, don't let your setting become a straitjacket. The game's the thing!
Your turn: How much work (like creating a language) have you put into your game world?
"Nobody believes me when I say that my long book is an attempt to create a world in which a form of language agreeable to my personal aesthetic might seem real. But it is true." - J. R. R. Tolkien
Stories require some kind of setting. J. R. R. Tolkien made his history and setting as a place for his linguistic efforts. But it worked pretty well for his stories! Was that much detail necessary even for the stories? I doubt it. I suppose what matters is whether you're designing a game, or making a framework for a GM to tell stories to players, two quite different endeavors.
Game vs. Framework
Unfortunately, many world builders are frustrated admirers of Tolkien who want to go into the past of their world, and perhaps show the “beauty and intricacy” of their conceptions. However, the distant past is rarely relevant to game players. Game players usually need to know what’s happening now and in the recent past, not what happened 5,000 years ago; or better, what happened 5,000 or even 1,000 years ago can be summarized in a paragraph. For that matter, what happened 100 years ago can usually be summarized. What matters in world building for games is the current situation, what’s likely to happen in the future, and what happened in the recent past that affects the present.There’s an element of self-indulgence in writing about the long-ago, which can be bad for tactical role-playing games like Dungeons & Dragons. The writer wants to share what he/she has in mind even though that doesn’t make sense for the game. It’s a little like films: when you have a writer who’s also the director you can get something that’s very good (Guardians of the Galaxy or Avengers) or via self-indulgence, that’s awful (many movies most of us never heard of).
There are game masters who see their campaign worlds as creative frameworks, and that’s fine, but expectations should be low that the world will become more popular than just that, an exercise in creativity (in much the same way Tolkien, as per his quote above, originally created his world for his language skills). If you're planning to publish your campaign so that others can use it, the detail can be helpful to future game masters. But for the most part, from a game design perspective, much of the lore and language probably won't come up in actual play.
Granularity
While I'm on the subject of what amounts to elaborate backstories for game designs rather than characters (see "Which came first, the character or the backstory"), I want to address granularity. For game purposes, changing your level of granularity in your history can be distracting. That is, talking about centuries of time, then switching to a timescale of weeks in order to tell a particular story (that’s too detailed to be useful in the game anyway) can confuse players, or worse, bore them.Yes, the Silmarilion does this; but that’s a compendium of bits left by Professor Tolkien, not a work he finished. You want to make a finished game, don’t you? Moreover, it wasn’t written for gaming. (Reading the Silmarillion is often like reading the Old Testament of the Bible.)
Retcons
Another related topic is retcons, going back and changing history by introducing new information. GMs sometimes do this to solve a problem in the history. Real-world historians in effect do this with some frequency, simply because of disagreements in interpretation, or discovery of new evidence, or even new political agendas that influence the historians. Yes, what happened, happened, but often we don't know exactly, so different historians have different versions of what happened, and certainly different versions of why it happened. This can work out in the history of your game world. Few people in the world will have access to "the historical truth" in such a setting, so it's easy and believable to change it as you go along.In other words, don't let your setting become a straitjacket. The game's the thing!
Your turn: How much work (like creating a language) have you put into your game world?