@Praxis : I agree with your post, the only problem being Marth. He has no real counters.
Also, Falco's counters are Kirby, G&W, Pikachu and maybe ICs. Lucario ? Not really, it's more an even match-up.
@Hylian : I'm not sure what you base your analysis of G&W / Falco on... It seems that you base it on your matches with Sethlon. I personnally think that if Sethlon beats you with Falco, he's just better than you :/
Seriously, how can a Falco grab a G&W ? If you get grabbed by a Falco as G&W, you're just playing bad, or being outsmarted.
As for the DK-Marth match-up, it's very probably 50-50... Fair against Bair, Tilts against tilts, horizontal recovery vs vertical recovery.... They very similar, Marth is just faster, and DK heavier.
I would be all for the ban of MK is Marth's only bad match-up wasn't MK... Let's find a counter to Marth and ban MK
Also I'm curious : People don't mention Falco - MK like a 50 - 50 match-up... Is it because of planking ? :/ I mean, without planking, Falco doesn't have any particular problems vs MK.