I don't quite understand this. The Planescape tiefling is obviously setting specific. It would be a bit strange to suddenly throw a PS race into the PH. Nor does the presence of a non-PH tiefling in the core book imply that the PS flavor tiefling won't show up in the Planescape setting book.
Imagine if I got upset because the PH dwarves weren't Dark Sun dwarves or the PH halflings weren't Eberron halflings.
Sure, I follow this. The issue only really occurs because the 4e/5e critter uses a word that already had an established meaning and lore before it came along.
It would be like if I said "Halflings are meachanized tenatacled elder gods that sleep beneath the world and wait to be awoken by mad cultists."
And then insisted that this is the sole halfling narrative in my big-tent D&D game. And that if you wanted to play the "original" halfling, you could, as an option, maybe, but you might have to wait for the "Greyhawk Campaign Setting" or make a house rule, maybe because mechanized tentacled elder god halflings were once referenced in some novel or drawn in a comic book and that's BRAND RECOGNITION, baby!
It's a cool narrative, but it's not what halflings are for a lot of folks. And the original halfling is perfectly fine, so there's no real need to redefine everyone's halfling.
If they just would've been call "Asmodear" or "The Faust" or "Devil-men" or "Turathi" we wouldn't be having this conversation. They'd be fine. I'd even welcome them into PS as a race likely to take an interest in planar affairs (much as I welcomed the Eladrin as such in my first PS4e campaign). But because the 4e team had a fetish for using evocative names for unrelated creatures (which, IIRC, one of Wyatt's 5e design philosophy articles even mentioned as not a great idea), now the people who use the word with its original intent are stuck telling people that some jerks went and redefined it and isn't that confusing and wouldn't it be better if they didn't?
So maybe instead of 5e continuing the trend of pissing in the cornflakes, it could've not done that, and let Tiefling also mean what it has meant since the '90's for a lot of players, and either expanded the definition or used a different word for the Turathis. But they doubled-down on the redefinition. Which is legit to be annoyed/disapponited by. It's not like I can't get another bowl of cornflakes, but that doesn't mean you didn't ruin THIS one for me.
Of course, useless to think about what could have been now. It's said, it's done, it is the way the thing is and now until at least 6e everyone using the term as it was originally defined to a player who's read the PH is going to have to take pains to remind players that they don't have to have handlebar-heads or chair-ending tails or red skin or be related to devils or generally play Setting Police over what someone is reasonable to think the books are talking about when they say "tiefling."
Best thing to do is treat Basic As Core, and add a PS setting to it so that the PH tiefling doesn't even come up. Which is a shame -- limiting options in PS is a bit against tone. But whatever. I got this thing.
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