I think it's kind of odd that you say no one has pushed that potential far enough to be considered when we have what is essentially Melee Falco on the list, alongside players like DF and Oracle playing ROB at high levels. GnW has not been pushed farther than ROB or Falco. There are similar numbers pushing GnW and ROB forward, and Falco has
years of development by some of the best smash players ever.
I'm also not really sure what you mean by "active hitboxes on most of his moves," since... uhh, I'm pretty sure most moves have hitboxes on them.
You're also heavily exaggerating many of his strengths. His combo game starts to lose potency at the high level with consistent SDI (ask @
Lunchables). His anti-projectile tools ("tools"? you mean the one, bucket?) are slow and so committed that it typically isn't hugely useful in high level play where these projectiles are often being used to approach, so he would be punished for using bucket. His projectiles don't do a ton to control neutral and can be unreliable to to their random element, mostly are just to tack on a bit of extra damage during combos.
Meanwhile, you're downplaying his weaknesses. He is not just floaty. He floaty, and the lightest character
in the game, meaning he is also one of the easiest to KO. Falcon can just dthrow knee and kill him outright at ludicrously low percents. He loses important MUs in the meta like Fox and against sword characters. Granted, he is a good character, but there is little to justify such a dramatically high placement.
I'm sorry, but there's no way that Jiggs has more polarizing MUs than Bowser's. Bowser loses to anyone with a decent grab game. Popo playing solo can chaingrab him to like 60. There are
plenty of characters that pretty much invalidate Bowser, and they are
common characters, too. Jiggs has decent or positive matchups with a good handful of high-tier characters like Marth and Roy. She is still very good at edgeguarding, contrary to what some people seem to think. To say most of her kills result in trades is also an exaggeration, since it's more likely that most puff kills are coming from edgeguards and not rest KOs, especially because of how punishable rest can be. It is
also an exaggeration to say that she will die off of a rest at 30-40%. It's
possible, sure, but would be far from consistent if the Jiggs has any idea how to DI. Even Melee Fox doesn't have a guaranteed kill on puff after a rest at that percent, but that's the range where it starts to become dangerous for her. Puff certainly struggles in PM, but there's no way she's the worst character in the game right now.
Regarding Snake: you're pretty much ignoring what I said on the topic. He has decent kill potential and a good punish game, yes, but I don't really think his shield pressure is anything to write home about. I don't think he has much of anything that is actually safe on shield, but correct me if I'm wrong. Snake's main issue is that he still takes time to set up those traps and options, and many of them can be used against him. He has few options to deal with pressure or combos himself that don't leave him fairly open, and his recovery actually isn't that good. I think it's a common misconception that he has a very good recovery. Sure, he can extend it by damaging himself, but cypher is incredibly slow and predictable. Marth and Falcon both, who are very, very commonly played and are high tiers, can simply dair straight through his cypher and immediately doom him. Snake is good, but he does not deserve to be the top of A tier.