I completely agree with you jarrod. By saying that the required skill for SSBM is nebulous, I am saying that improving is not based upon memorizing combos and building muscle memory. It is more about understanding and controlling space.
Unless you're friends are weaksauce Hyrule-only players, you need to know how to survive in many different chaotic environments, adapting to playing field shifts from items, and knowing how to use the current level to your advantage. Plus, it is four players!
I personally do not care for the game, but I do respect it. When I see truly skilled SSBM players go at it, I see oppurtunities capatalized upon not with base timing and controller motions, but with deep understanding of 2D space.
Still refuse to call it a fighter though.