Interesting what if.
Well, Sora would've ended up on Hollow Bastion with Riku then. Since neither of them would have the Keyblade at that point, I suppose that would be the end of the story... Sora and Riku couldn't really defend themselves against Maleficent without a real weapon and she would've had no use for them to want to play a game of manipulation like she did.
In that scenario, Sora dies or has his heart taken by the Heartless... Since Kairi didn't have Sora to hide herself inside of, I guess she'd have lost her heart? But if not she'd still be a world over in Neverland. Perhaps she could sneak onto Hook's ship with Pan and they end up over at Hollow Bastion since he flies there and use her light powers to protect Sora and Riku somehow? I dunno. That would all be very coincidental since Kairi wouldn't know where Sora and Riku are, and wouldn't recognize the name Hollow Bastion either (since it was called Radiant Garden when she was there). I guess it would make sense for her to want to try looking for them on another world with Riku and Sora not being on Neverland, and Hook traveling via worlds would be worth a try even without her knowing where Riku and Sora are.
But assuming the Keyblade appears to Riku or Sora at Hollow Bastion when they have to defend themselves against Maleficent, it's still hard to say what would happen then. Even if they could defeat Maleficent with that little experience, they still couldn't get off of Hollow Bastion without a ship. Unless the PoHs at Hollow Bastion by that point could help them somehow with their powers? By that point, Aurora and Cinderella at least would already be there, possibly Belle. If they have the Keyblade and have defeated Maleficent, they could defeat Hook and then SRK could use his ship to go elsewhere if they wanted? I suppose Ansem SOD would have to enter the story to shift Riku to darkness himself much earlier with Maleficent out of the way?
I guess it's possible Maleficent might think she could use Sora and Riku as henchmen and foster powers in them to help her even without the Keyblade, but Sora wouldn't go along with that while Riku might be willing to do what it takes to get him and Sora off Hollow Bastion and find Kairi. Thus, another conflict between them that could spiral, only with Sora having no options without the Keyblade to fight with.
