So how good did ZSS just get?
Notice something, everyone, that three of those characters have the same fall speed: Falco, Mega Man, and Roy. Little Mac wasn't on there, but he also shares the same fall speed as well. Also, all 4 of them share similar physiques unlike the 1.65 fast faller where you have big guys like Ganondorf and Ike and smaller to average-sized Duck Hunt and Bowser Jr. Hell, let's add 1.66 fast faller Meta "Stubby" Knight and 1.63 fast faller, large and in charge, DK. All 1.8 fast fallers are about average-sized and average width. If Wolf returns and keeps his 1.8 fast fall speed and let's say, for ***** and giggles 'cause why not, Cloud and say, random character... Squall Leonhart have 1.8 fast fall speeds, then guess what? You now have 7 characters with 1.8 fast fall speeds who all have similar builds. If a setup works on Roy, then it likely works on the other 6. There won't be any checking like, this setup works on DK, but will it work on Ganondorf since he's thinner or this setup works on Luigi, will it work on Link?
Shared attributes in a game with much more factors and differing attributes than in other fighting games... Is there a line when it shouldn't exceed a certain amount of characters? As mentioned above, I think it's fine so long as the characters aren't all similar in build. In that case, while it would kill Falco's edgeguard, he might prefer having his 3.1 fall speed from Melee, Roy might prefer having a fall speed closer to Ike which would hurt his vertical survivability, but help his passive recovery since he wouldn't fall down too fast before reaching the stage, and Little Mac and Mega Man would still share their 1.8 fall speed, bit it wouldn't really matter as it's only a, "if it works on him, it'll work on me", instead of' "it if it works on him, it works on all of us."
Shared attributes don't extend too far, though. Even for semi-clone, "Luigified", the Ken, or what have you, characters don't share much except for "EX" characters like Dark Pit, Dr. Mario, or Lucina who are more like different versions of the same characters rather than a different character who is a moveset clone of another - wow, convoluted, much? - with differing properties like the Melee clones. Inevitably, this does lead to Falco... Unlike other semi-clones, Falco's attributes not his moves are very close to Fox's. Take Luigi who has low fall speed, low air speed, slightly lower ground speed to Mario's average fall speed, high air speed, and slightly higher ground speed with only hop height being the same or take Captain Falcon and Ganondorf where they only share high fall speed, high weight, and slower air acceleration while other attributes are night and day. Between Fox and Falco, they share high fall speeds, low air speeds, average air acceleration, low weight, high walk speeds, and hop heights. The only difference? Fox's run speed is much higher and Falco's jump is higher. Between Fox and Wolf, they only share high fall speeds and high walk speeds while having polarizing air speeds, run speeds, weight, and hop and jump heights. If it's between Falco and Wolf, then low run speed is added as a shared attribute, but air speed, weight, and hop and jump heights remain different. This hurts characters - Falco - when they're a bit too similar to another. When people say Fox struggles against Luigi and Rosalina, the same reasons can be used for Falco. This is different when talking about Mario/Captain Falcon vs. Rosalina and Luigi/Ganondorf vs. Rosalina.