Couple of things about that community made tier list.
a) It was open to anyone regardless of skill level. As completely full of myself as I am, I do not for a moment believe that my *opinion* on this game, however informed or misinformed, counts for jack. It's why I'm content to contribute, poke people, discuss and learn (it has helped me uncover techs and improve my own game) but I absolutely refuse to make a definitive tier list. It is not my place, it is not the time, and even the people who are good at this game know approximately somewhere between jack and **** about eventual dominant strategies and final shape of the tier list. Please remember people actually thought Mario was the 5th best character in Melee and that R.O.B was high tier in Brawl at first (no doubt because of CPU beating Ken). Letting people of all skill levels vote without any sort of screening process is just asking for statistical garbage.
b) Taking tournament placement into account is also going to miss a lot of crucial data. Why? Seven characters, i.e. about 15% of the metagame, have only existed for TWO MONTHS. You are not going to be able to glean an accurate picture of how well Icies, Oli, Roy, Samus, Yoshi, Mewtwo or Kirby place in tournies because for the majority of the game's lifetime, they have not existed. This dramatically skews the results against them, since they haven't even been given any time to breathe, or be discovered by dedicated or high-level mains.
As unreliable as pure theorycrafting speculation is, the stats right now just reflect existing or widely accepted community perceptions of a relatively nascent meta. "Oli is trash because boring", "Foxco da bess", "Deeds has no neutral", etc. Regardless of whether I agree or disagree with any of these statements, it's not much to go on at the moment.
tl;dr we really need a lot more data points before we start going for some kind of numerical rubric. And even then I'm pretty sure it should be formed by a) people who know what they're doing and b) be a match-up chart rather than a bell curve of relative placement. P:M is new, but the design is very focused and heavily takes techs into account, unlike any other Smash game, so tier gaps will be much smaller almost by default.
(This is part of the reason why I think Jiggs and Ganon flag ... Their designs are overall poorer, weren't the 'happy accident' of Fox or Marth nor the deliberate planned-out kit that Snake received. They just hover with a half-baked playstyle that their makers did not even conceive and they suffer for it.)