Why can't you have your Planescape material packaged in a nice, pretty, Planescape supplement
I would love that. I hated getting just a Manual of the Planes & Planar Handbook in 3rd edition.
What you seem to keep ignoring is the fact that a ton of what you refer to as being "PS compatible" or "PS specific material" did not originate from the Planescape setting. A ton of the cosmology and monster ecology existed before PS was even a setting. A lot of what you complain about seems to be more about, "Why is this core D&D fluff being pushed on me in my core D&D fluff?" You may as well replace the word "Planescape" with the words "AD&D Manual of the Planes" or "AD&D Monstrous Manual". And really? You can't easily figure out how to dismiss something like the Blood War in your core game? You think even if you did have to dismiss fluff from your core game that your players are going to be up in arms? Do they care about your content that you create on your own and add to the core game? Cause it's not core material.
I don't understand your passionate dislike for Planescape. I think I've seen you bring up how much you hate Planescape many times before in the past years. Not that I care that you hate it. It's not for everyone. I just think it is strange how it has such an impact on you. The great thing about D&D is how we can have so much control over it. I actually didn't care for the PS fluff they added to 3.5 Forgotten Realms. So, I just ignore it when I'm using Forgotten Realms. I didn't care for some of the changes 3.5e did to the core planar stuff that differed from my Planescape stuff. So I simply ignore the changes and work around them while I run my 3.5 PS game. I don't like how Dark Sun tries to block Athas from the cosmology, so I ignore it and include Dark Sun material in my PS game because I like to use DS content. It's easy to make changes and I won't believe otherwise; cause I have been making these changes myself since the beginning of 3rd edition.
It's that any change to any planar material must be Planescape vetted before it can be added in. We cannot have different material since it would not be PS compatible.
That's just simply not even true. As has been pointed out time and again, Planescape is based on material that already existed, and then it was simply expanded upon in the PS setting (with tweaks here & there). Then that material and the PS additions were used as 3e core to some extent. Then they borrowed from that material and created another version for 4e, and made that core. So on & so on.
You're pretty much just complaining that you don't like current core material. It being from Planescape has little to do with things. Who cares if planar material was used in future core fluff and it originated from a particular setting? D&D changes, and it will continue to change. I'm sure plenty of material from other settings turned into core fluff in the future editions.
Yes, it does matter. Every single published adventure is going to use the core material. That means that every single published adventure that uses the planes must be Planescape compatible. Meaning I won't ever buy any planar adventures because I don't use Planescape and have no interest in it.
So you've never bought a 3rd party adventure and integrated it into your existing campaign world? You can't figure out how to get a planar adventure to work in your own setting when some of the content is different from your version? Complaining that you have to make changes to core is pointless. We all make changes to our game on a constant basis regardless where the original material came from. I've run dozens of adventures from 3rd party sources, converted plenty from other editions, and used plenty based in worlds that don't even exist in the D&D cosmology. It's never been an issue and it's hardly time consuming to do.
We cannot have abomination Slaad because Slaad MUST BE PS compatible. We cannot have eladrin on the Prime because Eladrin MUST BE PS compatible. We cannot change angels because if we have evil angels, then the Blood War doesn't make a whole lot of sense and that wouldn't be PS compatible. On and on and on.
So then we can't have good Drow because
core says they are an evil elven offshoot? Some far-off halfling town can't have Halflings that look like Hobbits cause
core says Halflings look like human children and the art doesn't depict them with big hairy feet? I can't have a Hill Giant Wizard because
core says they only have a 6 intelligence? That's really your argument to support your dislike of Planescape influencing core? Do you really stick to the core fluff like that? No wonder you feel screwed and are blaming PS for it.
Your beef is not with Planescape. Your beef is with the current fluff for the current edition you want to play. Whether the content was newly created for that core edition, or came from an existing setting seems moot. You're basically saying that if you never played D&D and joined a 5e game, heard about this war between 2 groups of angels called the "Heart's War", you would have no problem with that bit being in core since it didn't originate from Planescape? You'd also feel beholden to use this "Heart's War" in the 5e game that you DM and you wouldn't mind using it because it is 5e core and
didn't come from Planescape? Yer gonna run in to the same issues over content that you don't like even if they created an entirely new cosmology & monster ecology. Some of this content coming from Planescape has nothing to do with it.