Gimping Falco out of a GR is all a guessing game, but it's still an incredibly useful part of the MU. Yoshi really doesn't have an awful time getting the grab on Falco because it's entirely possible to grab him on landing if you get in during his lasering. It's also not hard to grab him once you set up a juggle, which Yoshi isn't bad at doing at all. Samus may have a Zair and UpB OoS, but what do those lead to? It's just little chip damage that puts Falco off his camp game for a brief moment before he returns to simply outcamping the character with no kill potential. When Yoshi gets in, he has a good boxing game, a threatening grab, AND the ability to keep Falco in the air well with his Usmash and grab, both of which can beat Dair, either directly or through outspacing it.
Edit: HAI SOCKS I SEE YOU LURKING