Regardless, I must say that however Yamato turns out in terms of good/bad, I'm glad he's not a kid. Anything is better that horrible "Momo/Yamato will be friends" theory and glad that he's actually strong enough to just trump over an F6.
Idk, part of me still thinks he's setting up a battle with Luffy instead, and not actually trying to be his ally, but we'll see.