I suppose it matters whether we're talking about the matchups being played perfectly or accounting for quite a few mistakes from each side. If we're talking about the matchups being played perfectly, Falcon is completely boned vs. Spacies and Sheik, but once we start talking about a Spacie or Sheik that makes more than a couple punishable errors, it becomes a whole lot more manageable. The same is true for Jiggs in the CF matchup. If the CF stays near center stage and camps appropriately spaced bair/uair/dair, there's pretty much not a **** thing she can do about it, but once we account for a few punishable errors, she can punish harder than any other character in the game.
so basically, I think right now that the top level Falcon vs. Sheik/Fox/Falco is pretty close to the same as Falcon vs. Jiggs, but as the best Falcons meet H Box and MaNg0 more and more, the limit of the matchup as Falcon's skill increases will favor CF. On the other hand, Sheiks, Foxes and Falcos who play vs. good CFs more and more will start to put those matchups back to being soundly in their characters' favor.