Let's just hope he doesn't make the same mistakes Terra did.
Who do you mean? Sora? Nah, why would he?
And Riku? Nope, neither as he already DID make the mistake and turned around before it was too late. Granted, Terra was pretty much screwed way earlier due to Master Manipulatornort pulling the strings secretly.
Sora wasn't training to become a master basically his whole life and it wasn't a dearly held dream of his.
Exactly this, the title of "Keyblade Master" doesn't mean so much for Sora as it does for Terra.
They have completely different mindsets about it.
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On a side note of Sora not becoming master, I'm calling it now. Sora will go in KH III (first alone, later joined by Donald & Goofy) to rescue Aqua, Terra, Ventus, Xion, Naminé and Roxas while Master Riku, Master Mickey and Apprentice Wielder Lea fight to stall the Xehanort Army and buy Sora time to assemble the execution squad. ;P