sigh I figured that your garbage Sheik list was just one blunder @
TheReflexWonder
but...
Nerfing Falcon? Falcon??? Falcon is a character with extremely noticeable, exploitable flaws. He has a linear and easy to gimp recovery, garbage disadvantaged state, and is easily comboed due to his physics as a character. His really good dash grab, damage output/disjoints, and explosive attacks make him a pretty well-balanced character all things considered. He's not even Top 10 and barely Top 15. Any and all nerfs to Falcon are unjustified. His dash grab isn't "like Melee Sheik". He can't get regrabs. He can get follow-ups off his grab and his dash grab is super fast but like...so what? Falcon is an absolutely fine character that is overloaded with no silliness to speak of.
Figure I'll just post about the Sheik stuff here again for a bit more exposure. Sheik does not need a lot of nerfs. She is not an absurd character that is super far from the rest of the cast in terms of dominance. She's by far the tamest best character Smash has ever had with a very noticeable flaw -- difficulty confirming kills. Do I think that Sheik deserves certain nerfs? I do, as her current design has some things that are perhaps a bit too good. There's no point in killing her as a character though. Yes, those nerfs kill her as a character, and moreover are mostly unjustified.
There's no point in nerfing Jab 2 at all. She has nothing guaranteed out of her double jab; setups out of her double jab really only work because it's kinda difficult to react to, and most players don't understand that they can actually get out of follow-ups in a lot of cases (some characters with bad frame data can't, but that's really neither here nor there because characters with bad frame data can't get out of a lot of things). Her multi jab is a pile of **** that can be DI'd out of and punished really easily. There's just...nothing offensive about jab. That's also not even really a nerf because the point of Jab 2 is to link out of Jab 1, and the point of her double jab is just that it's her fastest option at close range and can potentially set up certain things.
The fair nerf proposed is more along the lines of unreasonable nerfs. Forward air is literally Sheik's game. It's her spacing, her approach, and her punishes. Sheik as a character is not good if she can't space effectively with forward air. The current issue with forward air is not lag, but sheer range. Forward air beats pretty much everything because the disjoint is so big that it can be spaced really really easily. Slightly decreasing the range makes Sheik put in more effort to space with forward air, i.e. committing a bit more. With the given nerf, Sheik can't space with forward air on shield without landing with lag. That's over the top.
Needles are already unsafe on hit at close range at low-mid percents, in case you didn't know. What's needed is a nerf such that needles don't send opponents into tumble/pop them up as high until much higher percentages, which is the thing that's really problematic about needles as they stand (single needle juggling is a little stupid as needles send opponents into tumble at like 105ish%). Pretty sure this entails a decrease in kbg, not sure how much but I'm thinking that they shouldn't send opponents into tumble until around 135-140% or so. Maybe even like 150%. This is a reasonable nerf that fixes the issue with single needles at high percents.
I like the intangibility reduction idea with vanish. That's something which I think absolutely makes sense because it forces Sheik to recover more carefully and makes vanish a bit more realistic to challenge. I don't see the removal of her ability to autocancel it on-stage at certain angles as needed; she has limited angles to autocancel and therefore can be exploited in that regard, and there's really nothing wrong with the ability.
Nerfing bouncing fish is silly because there are no issues with the move. It's not an issue offensively, so why nerf active frames? It's not a broken escape option either. You can chase it/read it and punish it regardless. Seriously, if Sheik gets away with Down B every time, you're screwing up. This move needs no nerfs at all.
Another possible nerf that would work is slightly increasing the end lag on grounded needles (like by 5 frames or so) to make them a bit less crazy. Her needle zoning is already a little overrated. It's more her mixups and baits that she can do with needles that make them so good, which you can't really change without fundamental mechanical changes.
Basically, decrease fair's horizontal range a bit, decrease needles kbg such that they don't send opponents into tumble until higher percentages, decrease intangibility frames on vanish, and add like 5ish frames of extra lag to grounded needles so that they have a bit more commitment. Keep her bair like it is, don't buff it. There you have reasonable nerfs that make sense and don't murder a Sheik as a character while actually balancing her!