But in prior editions you could in fact construct more realistic or low fantasy settings by simply choosing from the best resources and limiting players to appropriate choices, and not feel like you were excising 80% of the game in the process; even if the base assumptions of D&D weren't favorable to low fantasy, the systems and their endless splatbooks provided plenty of support for any sort of game you could imagine, and the OGL turbo charged that. This was quite doable in 1E, 2E and even 3E, and only really went away as a viable option with the arrival of 4E.
Could you though, really? Like, let's be realistic. If you're making low fantasy you're chopping the wizard, the dwarf, the elf, probably the halfling, I'd say you want to chop the cleric as well. That's already 3/4 of the most basic races and 2/4 of the basic classes. You're excising a lot of stuff right off the bat, to say nothing of how many creatures just aren't ending up used. How many items are being thrown on the chopping floor. So much of the work is being thrown away I'd easily say its at least 80% even when we're talking the most basic books of Basic, not even going into the expanded line.
D&D was, word of the creator, a work that had a cleric introduced just to counter a vampire. A game you could totally play as a balrog in, as long as it was a young one. A game where people took Deities and Demigods and saw it as an extension of the Monster Manual and set about forcing the gods to mine out salt in the ruins of a destroyed planet. I'd argue its never really been favourable to low fantasy
It doesn't matter. It was mentioned previously that the official setting in question that the particular player i mentioned was trying to totally rewrite in question was eberron. The easy context free example you just quoted used player trying to bring StarWars Jedi into a star trek game. This shouldn't be question that needs answering but I've also needed to say no that doesn't fit the setting with Ravenloft darksun and Thay games.
I mean, if you want Star Wars stuff that's easy. Grab psionics. Eberron has enough psionics and 5.14 even has a class that's flat out just rules as written intended to fulfill that fantasy. You can tease out what people want from something and provide assistance in making it happen. D&D has plenty of "Yeah this is totally just X". Want to play Elfquest characters? Ghostwise halflings. Want to play a Protoss? Xeph.
Ravenloft is a grab bag anyway. Ironically given how it functions its the setting most applicable to having a Jedi in it due to how that all works
YES tortuga is going to be a problem sometimes:
darksun doesn't have islands or costs and I don't have any interest in constantly figuring out where tortles fit into darksun if I'm running a darksun game where there are already things going on. That is an especially important and inflexible because the players wanting such a thing has already demonstrates that they have zero willingness to engage with the setting as much as would be needed to simply have their character fit the setting rather than call for the setting to be modified for them.
Similar problems can exist if I'm running a Ravenloft Thay eberron or any other setting game and the critical problem is that the player's character is already being a disruption without even having been created yet. I gave you an example with Star wars and star trek to avoid just this sort of endlessly more specific edge case whataboutism devste... Luke Skywalker does not belong in the star ship enterprise and it doesn't matter how easy it would be for the gm to figure out an excuse that fits because the conflicts are only going to grow more problematic to deal with over time as the campaign progresses
Well, then you're a desert tortle. Because desert turtles exist. Or you're from the Last Sea with all of the surfing lizardmen, because we got to be reminded that Dark Sun is the setting with the surfing lizardmen. Rules as written, Yuan Ti and Kenku are completely fine and extant in Dark Sun, and there's nothing saying they're extinct there, so they could exist.
Ravenloft isn't a problem, as designed that setting just grabs people from everywhere so it could easily just grab a tortle from anywhere. Thay isn't a problem, Tortles exist elsewhere in FR, you're just from there and ended up in Thay in your travels. Eberron isn't a problem, everything from D&D exists somewhere in Eberron so, yeah, Tortles are in there by default. There's a wide massive ocean the books don't go too hard into and you're wanting Keith's blog to apply more
Luke Skywalker may not belong in there but you could easily write a character who starts off the same, a young farmboy from a desert planet with high piloting skills, and use that to play a character in Star Trek RPG of Choice (or that other one with the complicated scenario) easily, and that isn't too hard to fit in. Things go different of course, but the root idea can be played
Rust monsters and flumphs are not playable species.
Tortles are exotic in the sense that they are rarely being played, just because they apparently were invented in 1986 does not change that. Elves and dwarves are not exotic, tortles are.
A setting / table not having eg elves is rare, pretty sure a setting / table not having tortles is the norm
Xeph are exotic. If its been playable in one edition (let's be honest, 3.5E) and no others, then its . Tortles have been playable in multiple editions and have a Dragon Magazine article about them. They're not really exotic, to say nothing of how standard "Yup, that's a turtle man" is given the animal people D&D already has.
Being playable in three editions (AD&D, 3.5E and 5E) is not exotic at that point. Its not the most common but they're outdoing past mainstays like the saurials or lupin.
oh, the setting that apparently sold less than 20k copies? You are making my case for me
Red Steel is a sub-line of Mystara which was a very well selling setting overall and probably should be included with the rest of it, not just by itself.