I genuinely cannot believe people are still hung up over Sora not being named a Master.
Spoiler: It's never going to happen. Sora as a character is specifically designed to not be the master. He will always be that way.
He will always be a naïve, impulsive, rough-and-tumble amateur because he's supposed to be a normal kid. No destiny for greatness, no exceptional skill, no noble lineage, nothing but the will to do right and to protect his friends and it's that quality alone which takes him as far as he goes. He's an analog for and a message to all the completely average people playing Kingdom Hearts.
Failing his Mark of Mastery did not negatively impact him in any way. Yen Sid could have named him Master because he fulfilled the task laid out for him (seal the Sleeping Keyholes and acquire the power of waking). He did complete the designated task. But he's not a Master. He never will be.
You'd think people would get over it as quickly as Sora did, because of how little it actually matters to anyone, especially him. But I guess not.
I never once got that impression from the story of KHIII. Yes, Maleficent and Pete pick on him and we're meant to believe Sora is weaker as a result of getting got by the old man. But that's not the game trying to tell us Sora's a useless piece of shit.
It was well established in DDD that Sora would be the one who could bring back the lost Keyblade wielders. That's why Yen Sid sends him out to find the power of waking again even though Riku already has it. Because he's not a useless piece of shit. He's their ace-in-the-hole.