They can just replace succubus with that demon spider in Legion, instead of seducing someone, the spider can just use their web ability to achieve the same result.
Nope, class quests, even if removed, retain canonicity in this regard.
We do not learn to summon a succubus by ourselves upon reaching level 20 by inhaling air.
Especially given the new quest to summon a voidwalker from the void via a grimoire that requires to subjugate the voidwalker is indeed the same canon as the previous versions of the quest.
Because we canonically summon a demon/aberration from a grimoire ritual, and then enter into a contract with it (for all the rational demons) or forcibly subjugate it (for the felpuppy because it is a demon dog and void aberrations because they require being subjugated as otherwise they’d consume reality).
While for gameplay reasons we can cha cha slide over to Demon/Aberration Renaming NPC and just “randomly select a new demon”, canonically this is not the material reality.
Canonically each time we are “changing our demons”, we actually would have to do the ritual again and enter in a contract with a new demon (or subjugate them for the 3 minions aforementioned) and release the previous demon (or aberration) from contract.
Unless of course warlock stables are added, in which case you could just endlessly keep any demon in a giant grimoire and just pick your favorites any given day.
All of which you would know if you read my warlock stables post
Dude nobody care about your stupid thread, basically yes you change demon and not every succubus share the same thought as the one you met in the Classic quest.
All succubi feed on the hearts of good men, and require sustenance to be worked with as part of the contract.
Our Observer freely entered into a contract with us because he greatly enjoys eating and observing different magics (Green Fire Legacy of the Masters questline), as is his nature.
Our Eredar Wrathguard loves killing things and is happily in contract because we are nicer than the Burning Legion generals, and he was an Eredar on Argus, etc.