You still haven't told me how he ever "used" the princesses at all.
He lost Aurora's heart but HE DID CARE because he was moping about it through the entire game. Did he get it back? No. But that's only because Maleficent disappeared with it. How is he supposed to know where she is? The only reason Ven knew about Maleficent's whereabouts was because the 3 faries told him. With Terra, he didn't have that. Plus even if he somehow found the castle, is was blocked by fire that only the 3 faries could put out. Terra DID care but he couldn't do anything about it. If he didn't care he wouldn't constantly being talking about it in all the other worlds.
Terra TRIED to find Snow White so he could explain it to her but he couldn't find her. Again, a bad example.
How the heck was Riku "helping" Sora by using the darkness? The whole story Riku was on this mood of "Oh, Sora's not my friend anymore, I hate him, he's so selfish!" He NEVER used darkness to help Sora.
And no, you haven't proved that Sora is smarter than Terra. AT ALL.