So, an ultimate air dodge punish from Captain Falcon is a bad move? Not only is it a good air dodge punish, but you can set it up from a Uair, a common and very good move Captain Falcon has. It may be situational, but it's a good move. In the same scenario, apparently Toon Link can setup his Fair out of Bombs which I think Peach can do with her Fair with Turnips. DK? He can setup his Fair out of cargo U-throw which alone is a good move when it covers behind, above, in front, and below him which in a similar case, Triple D can easily get a Fair out of his D-throw. Greninja can sort of 50/50 people from Dtilt or D-throw with Fair. The only Fairs I don't think you can setup with are (Dr.) Mario, Yoshi, Ganondorf, Link, and Shulk's. They are slow and situational moves, but nevertheless, they are good moves in those moments.
Yoshi approaches and spaces with Fair. Yoshi in Brawl used to use Bair instead, but because at launch, Bair wasn't so great as Brawl, Yoshi players don't use it. Now it has auto-link angles, so it won't flub up hits and you can do a Bair spike to Up Smash. Can Yoshi use Nair? Yes, but it doesn't have the hitbox or the strong hit as Fair. With Yoshi's air speed and fall speed, he can drift in and out with Fair. That's what makes it work: the drifting means you don't really where Yoshi's going to be. Who else does that? Peach. Peach has 2 common options out of a low float: Dair pressuring and Fair spacing and baiting. Vegetable in hand, she can cover her approach or make you guess if she's going to throw or not. Yoshi can sort of do that with Egg Throw by pressuring you with eggs. At the same time, it's the ability to weave in and out that makes Peach's a good move. Oh, and it's her common kill move too at frame 16.
Results? So, the common complaint of Yoshi being overrated, Japan doesn't understand how to deal with Yoshi, or the fact you can look at the PR thread and see many Yoshi players? Yoshi might not be top 3'ing tournaments, but being in the top 10 is pretty damn good for an overrated character with Captain Falcon syndrome of doing well, but not doing well enough to beat top tiers. Toon Link is not played as much, but Zan and Artemis - she? was at EVO, right, but lost to something that I don't remember - do pretty well. Then you have Ganondorf with results from Ray Kalm in Canada and I'm not sure, but Gungnir in Japan. For a character that pretty much shouldn't be winning is doing well is fine. What about Peach, Link, DK, or Shulk? For Peach, she's a good character who with the few players she has from lloD, Pink Fresh, SlayerZ, and even freaking False, she does fine. Link pretty much doesn't have much nor do Shulk and DK only has like DKWill as the most notable player. Hell, Mario only has Ally and Bowser Jr. only has Tweek making dents while the rest are doing so-so like many Yoshi, Ganondorf, Shulk, Link, Toon Link, etc. players.
How about Sonic's frame 13 Bair? Slow isn't it? Low-level play would be able to easily setup it after a Spin Dash jump. That's why it works and even alone, it works because of Sonic's good ground and air speed. Same with Fox's frame 9 Bair which Fox players will use to pressure shields and approach. Why? Good auto-cancel, good shield push, and if hit with it, good damage. After that, Fox doesn't have anything as safe for aerial approaches. In a way, Fox is doing the same thing, but with a frame 9 Bair instead of a frame 16 Fair. A character that is well-known for his fast hits and fast ground speed relies on a slow aerial for aerial approaches. A frame slower and we've got Captain Falcon, Ganondorf, and the Pits' frame 10 Bairs. Ganondorf might not have as much of results, but Captain Falcon and the Pits definitely do. These frame 10 kill moves that early on people suggested Captain Falcon use as an approach? The frame 10 Bair that people are complaining because it was powerful and others are complaining that it was nerfed by 1%?
Oh, and for the record, you don't space with Greninja's Fair. You're better off using his Bair instead which Link also does.
Edit: Forgot about this: my original post was asking what your point was. Why did you just pick Fair and after finding out it's frame 16, just sigh, and say Greninja's in a worst spot than possible?