I don't think R.O.B. has that big of an issue with Fox, since - unlike Falco - his laser can't stun us (even though it's still annoying).
As for Olimar, how does R.O.B. have a disadvantage against Olimar? R.O.B. has Robo Beam to tack on damage, and can fly a thousand miles off stage to gimp the hell out of him. Yeah, Olimar has camping/spamming abilities too, but once he's off stage, we can just keep him off. Of course, it does require some prediction for when the foe uses Pikmin Order to give them super armor. I smell a conspiracy. o.O