We have a habit of only talking only about Charizard's strengths. Rock Smash, Flame Thrower, Jab, Dash speed. And he does have some pretty awesome strengths. But strengths alone don't determine your spot on a tier list. We're forgetting one crucial detail here; match ups. As long as speedsters and zoners are favored, Charizard is always going to be at a disadvantage. He's just far too easy to combo, and far too easy to keep at a safe distance.
Let's look at the guys in apex; Sonic combos, Sheik Combos, Diddy combos, Rosaluma zones, Olimar zones, ect.
Now one tournament isn't going to tell us which characters are truly the best, but it does give us an idea of what works best in this game. And what does work doesn't look all that pretty for Zard.
Maybe I'm wrong. Maybe Charizard is insanely awesome and capable of completely destroying even the greatest Sonic and Sheik and Rosaluma if played correctly. But I don't think we should be so confident that he will be.