How many of you guys are top players or play against them regularly at all?
I never said Fox and Falco are unbalanceable. It would even be simple for Fox, and I think Falco would benefit a lot from a nerf to the d-air. The thing about nerfs... Have you guys studied game design and fighter theory? I'd point you toward Sirlin's blogs, from when he was rebalancing the Street Fighter 2 HD Remix. He talked about nerfs, and how it's best to avoid them, because "good" in any remotely balanced fighter means more viable options, and more viable options in turn makes the characters more fun to play and play against. You want every character to be great. The difference here is that... no character could be made any better than Fox and Falco and still be considered reasonably balanced. Think about it. There's practically no way to do it without breaking the character in some way. They have no real weaknesses already (except Falco's recovery, you might argue, but I'd compare that favorably to lots of characters).
My fundamental curiosity here is to see if programmers who were never top-level players can become good balancers. Design and balance are two separate fields. Sirlin, whom I mentioned above, titles himself as both. He designed Kongai, the card game for Kongregate.com, but he balanced the SF2 HD Remix.
I wouldn't ask you to make them play differently. I'd only ask you to make them more vulnerable. And that's a nerf which is worthy considering, even if nerfs in general are a bad idea.
Edit: Another thing Sirlin did, and this was very controversial, was to remove unneeded physical complexity, by simplifying various characters' special inputs, so that they were easier to perform reliably. That fact aloned buffed Cammy.