Alright, you may be a decent samus player (not much way to prove the point) but what you don't seem to understand is the fact that tier list are based on meta and potential of a character.
I understand pretty well, actually.
No person is going to have an accurate tier list without hours of game time or footage on a character. Tier lists are also someone's own personal opinion, if you look at a Melee tier list there will definitely be consistencies but they aren't all exactly the same.
People can make their own personal tier list, but to think tier lists are "someone's own personal opinion" is false. A number of players come together and discuss each character. I can't say how it's done, since I'm not part of the Back Room, but I'd take a guess that frame data, match-ups, tournament results, and a number of other things are discussed.
We also have several top players aside from Zer0 who say samus is much worse than any previous game sure esam may not be the best smash 4 samus player, but he understand well enough what each character has in their toolbox.
ZeRo was a top player, but that's irrelevant to knowing a character. As for ESAM, I'll let ESAM speak for himself, rather than a stranger on a message board.
Just because a character is low-tier doesn't mean they're bad per say,
The reason why a character is placed specifically on a tier is based on facts about those characters.
any character in the right hands can be good and win a major. For example look at plup's Luigi (mid tier but still) or m2k's pichu.
And with regard to Plup's Luigi or M2K's Pichu, how consistent are these results? Sheik is a very good character in SSB4, but after her nerfs, the only player who has recently ever won a national tournament (Smash 'N' Splash 4) with Sheik was VoiD. And you can't dismiss VoiD as a bad player, since he's the best Sheik player in SSB4.
A tier list, frame data, or certain advantages don't limit a characters potential, a player does.
I disagree. You cannot change frame data, no matter how hard you try. It's fixed. Having numerous players play each character speeds up the process of who is actually good and who isn't. A player is only as good as his/her skill, strategies, and mindset. Yet, this same player can perform way better by picking up other characters at the cost of stigmatization, viz., "x is carried by y."
Never take tier lists that seriously.
I haven't since SSB4, probably because rage affects the outcome most of the time.
The creator of the thread said to not take his post that seriously, it's clearly something he did for fun. And for the record I've had a significant amount (8+ hours) of time with the game, and played a lot of samus in both smash four and melee and can definitely vouch for the fact that she is with out a doubt low tier at best if not bottom. You need to realize that samus doesn't work very well with the engine, this is nowhere close to smash 4s engine it's just not the same.
Like you said, tier lists are personal opinions. That's your words, not mine, and I don't believe you, but I might as well address your inconsistency. And for all I know, you don't even main Samus. Actually, from the looks of it, your character icon would suggest you don't.