Ok I can see how Ridley would be more suited to represent Smash as the main villain. I'm aware that Ridley was the cause of what Samus has become. I don't have Ridley's background researched, so I could be wrong when I say that he has nothing to do with the Metroids. And seeing as the franchise is called Metroid, Dark Samus just seems like she'd be more suited to represent Metroid, since she is Metroid Prime. Of course, the Prime series is only three games, but it's the most recent and probably more popular of all of the metroid games. I don't keep up with game sales or anything so that's just an assumption.
But yeah, I do agree that, even though Ridley doesn't have many connections to the actual metroids in the game, he is the main villain. In the end, they both have almost equal legitimate reasons to be in Brawl as central villains to rep Metroid. You like Ridley though, and I like Dark Samus, which is why this debate will keep going if I keep going.
Ridley and DS for Brawl!