Hussar
Legend
enh? This seems to be a characteristic of any proponent of any even remotely controversial bit of D&D fluff, and is certainly not a peculiarity of Planescape fans.
/snip
I think the difference here is just how pervasive the Planescape and Great Wheel flavour is. We're not talking about a single race in the PHB, like Dragonborn. After all, we can just not use Dragonborn. It's not like the game radically changes if you don't.
But this infects every single aspect of any planar elements of the game. Not just demons and devils. The elementals get sucked into this, as do all outsiders of any stripe. After all, they all have to get slotted into their properly balanced plane/demiplane/pocket dimension with their exact opposite counterpart sitting on the other side. It's ludicrous.
If it was limited to a single setting and series of books for that setting, I'd have zero complaints. But this affects every single game played. After all, any cleric or divine caster gets roped into the Great Wheel. Every summoner gets sucked in as well.
And, because it affects PC's, and the DM's setting, it's a royal PITA to excise or ignore. Sure, hate the changes to Forgotten Realms. Ok, I'm down with that. But, the only thing those changes actually change are Forgotten Realms. Bringing back the Blood War and all the baggage affects every single game table.
So, why do I suddenly have to do all the work, again, of stripping out all this unwanted (by me) flavour? Why not keep the Planescape stuff contained to Planescape and give me a fairly generic core with a couple of suggested cosmolgies without any real reference to any of them in the core books?