I both agree and disagree with Edgy Lord here.
In terms of the neutral, I think we've almost completely explored this gamestate, and for the most part, we know where certain characters rank within the neutral. Top players use perfect pivots, foxtrots, and movement options pretty consistently. Frame data repositories allow us to see what is safe and what is not safe. Then, deductive reasoning and practical applications allow us to get a pretty good idea of where most characters rank in the neutral. Sheik and Diddy are good because they are fast and they are safe. Ganon and D3 are bad because they are slow and unsafe. Much time has been spent exploring the neutral, and I think by now most characters' potential to develop their neutral has capped already.
Advantaged states, disadvantaged states and punish games, however, are nowhere near optimized right now, and that includes edgeguarding. These game states are woefully underdeveloped compared to the neutral, and I think it is very possible that certain characters are really being held back by this. As long as there are footstools and weird tech mechanics in this game, there will more than likely be unexplored follow-ups and rewards available for characters for winning the neutral. Earlier I saw an example of this when someone cited ESAM's utilt footstool video. Even if no amount of labbing will make pika's range any less pitiful or make his neutral much better than it is now, we can find rewards and optimized punishes that, even if they don't actually make his neutral better, can make him a scarier character to fight.
That's just one example, too. Would Megaman be where he is right now if metal blade footstool was never a thing? What if Greninja mains had just called it quits after seeing his frame data instead of labbing his nair and footstool shenanigans to make his punish game really scary? What if Sheik mains never bothered exploring her other kill options after the nerfs, and instead of discovering needles->bouncing fish, ftilt 50/50s or bair crossups, they just declared that the character's potential clearly peaked? Same for Bayonetta?
I have no doubt in my mind that there are still undiscovered punishes and follow-ups in this game that could change the metagame, even if the neutral game is very close to optimization.