The only real point of contention I can see against Marth dropping is, well look at the characters right under him. The only ones making real strides forward in his place are IC's and ShroomeD-oc; I can personally see IC's capable of making that jump, but that might just be the IC main in me.
Falcon has been doing the same **** for 11 years so any movement of his is a direct result of other characters moving forward rather than him moving back. That's where the "Marth problem" comes from. Sheik, Marth, Falcon, Ganon, and to a much lesser extent, Fox are not necessarily doing worse, even relatively, other characters are just being pushed forward and explored more, while these five "hype machines" are sticking with the same guns, trying to show they still work even with the new blood.
Now, whether they do still work, and if they do, if they work as well, is entirely where the root of the argument unfolds. The fact of the matter, and one that I'm sure every backroom member looking at tentative votes is focusing on, is that there are players of characters preforming equally against and out-preforming the best players the characters currently above them can throw out, and that matter can't simply be ignored.
I'd really like to discuss Fox Falco more unless that has been done to death with recent matters taken into account.