So, I might end up rambling for a bit so I'll just try to summarize first my main thoughts about the whole "more Disney villains" topic up here then go into detail further down.
Mainly: I think there is a very tricky line that a lot of people don't really consider when you end up throwing multiple villains into the same room together. One is going to outshine the other unless you write very, very carefully or they are working together. In a game like KH with its own OC villains--if they are going to have a presence in a Disney world at all, they are naturally going to have to butt heads with whatever Disney villain is already there. Your options then, are to have the Disney villain shine, to have the OC shine, to have them somehow work as a team, or to set up a situation very elaborately so they don't step on each others' toes. If the writers are trying to follow the plot of the film that makes it even harder as the Disney villain has a very rigid goal and process for carrying it out. So if the Disney Villain is the ultimate bad guy, what is the OC villain doing? Nothing? Jumping in to say random stuff then leaving for no reason? (looking at you DDD...) Having more Disney bosses can run a very real risk of making the Disney world seem out of touch of the "main story" because the OC villains may have very little influence or presence there. Not saying it's impossible or they shouldn't try, I'm just saying it's something I think a lot of people don't consider, but should. Especially since Disney worlds not being "relevant" is another huge complaint people have. Unfortunately, it may be the case that often tying a Disney world into the "main" story of the game = forcing the Disney villain to take a back seat so their "plots" don't outshine whatever the evil OC is attempting to do.
@AmaryllisMoth I'm going to go out on a limb, but personally, that's really is a big issue with the original villain's roles being in the Disney worlds and just being there and not do much while just using the Disney antagonist for their own uses, like Marluxia to Mother Gothel, and Ansem, Seeker of Darkness to Maleficent and her council of Disney villains. Speaking of Marluxia:
In another example, let's look at Tangled. Let's pretend that Mother Gothel hadn't been influenced by Marluxia earlier to make her Darkness go all crazy and warp her into a Heartless. That instead, we get her as a boss fight. We show up to the tower and she's spitting magic at us out the window and the entire fight is a dodge race to climb up to the window to save Rapunzel and Flynn (I dunno). So we beat up Mother Gothel, save our friends, everyone is happy and yay.
But then...wouldn't that only make the "irrelevancy" of Marluxia in that world EVEN WORSE? If the above happened then literally all Marluxia would do in that world is show up, ramble to Sora about their big-bad villain plans like an exposition idiot and then just...leave. After putting Sora to sleep for no reason just for the lulz, I guess.
Instead, what the intentions were, I think, was to have Marluxia elaborate "we are gonna get yer princesses if you aren't careful" then have him outright prove said claim by showing he was willing to manipulate people, turn them into Heartless, endanger the general population, etc all in order to kidnap their target. It was a thinly veiled threat that if Sora and co don't move their butts and get the other Guardians then Repunzel is in very. real. danger. People may disagree with the storytelling, but fighting a Heartless version of Mother Gothel vs herself as she is kind of serves a purpose, in a way.
That was the entire point of the Tangled world: 1) to help Sora understand "love" a bit, in a way and 2) prove that the new Org is def gonna straight up murder his friends if the Guardians don't get their act together.
If it was just a fight against Mother Gothel than half of the entire purpose of the world is just thrown out the window without significant rewrites.
I'm sorry but even if Marluxia thematically fit the world, neither Rapunzel and Mother Gothel respectively never brought up his name again for the remainder of the world after their first and encounter with him which made his appearance very pointless in the world. At least with Monstropolis, Toy Box and San Fransokyo, the inhabitants do acknowledge the Organization XIII member (Young Xehanort, Vanitas, and Dark Riku) and not brush them off like it never happened compared to Marluxia's role in the Kingdom of Corona, particularly the former world when Randall had a "teamup" with Vanitas. Personally I think Xaldin in Beast's Castle did it much better on replacing the Disney antagonist (e.g. Gaston) than Marluxia if you ask me.
On top of it, I'm fine with not battling Mother Gothel as a boss cause she isn't really a fighter in the film only using her lies and deceit to her advantage, plus having a dagger would make her boss fight not interesting, I think she's the only Disney antagonist, along with Hans from the revival era I'm okay not fighting as a boss
I think this could be a discussion for another thread cause frankly, I am in the middle of the OC Villains "teaming up" with the Disney villains if they are just literally being just "there" in the Disney world and just using them for their own selfish uses (Marluxia - Mother Gothel; Vanitas - Randall; Ansem, Seeker of Darkness and Xehanort to Maleficent's Council in the first KH Game).
To answer your direction question directly about villains, though: So long as the fights with the villains aren't there just to BE there then cool, bring em on. Personally I think Pixar in general is really great in having decently developed villains that make sense for their own story. Having Lotso as a villain in Toy Story makes a lot of sense. But...would Lotso attack Sora? Eh...I mean maybe if he was with Woody? But I don't feel like a lot of Pixar villains would really be motivated to care about Keyblades or listening to Org members tell them to kill some random kid. The Pixar villains aren't really THAT villainous outside of the contexts of their own story (which is kind of what makes them so good). They are mostly just opposed to the heroes in their own, sometimes justifiable way, until their plots kind of get out of hand. Disney villains on the other hand are generally a bit more...on the nose? about being evil. I can easily see Jafar being manipulated. Some random money hungry chef or food critic in Paris? Ehhh....
I think Pixar villains are ambiguous enough that unless they are directly causing harm to Sora's friends because the plot is mirroring the film plot there isn't really a reason for Sora to beat up some old guy in a jungle living in a dirigible museum with a gang of talking dogs.
And if it is an original story plot it's...even harder to justify. Personally I think Pixar worlds are unique, amazing locations all in their own right and I think they are better suited as being sources for new unique KH-centric plots that don't overlap with the original Pixar movie plot, or do so as little as possible simply because the pixar plots are generally more intricate, the villains more nuanced, and the stories are much harder to capture in KH-style bite-sized chunks.
Then again some of the later Disney villains released after Mother Gothel and Dr. Facilier have also become more nuanced and act very reminiscent to the Pixar villains especially with their plot twists reveals like Hans, Callaghan, and Bellwether.
