To be honest, this is kinda generalising but I get what you mean. It is basically only Ike, Shulk and Captain Falcon who get this sort of "People play them because they like the things they say as opposed to how they play." treatment, and it's pretty much down to two words: Internet fads.
If I had a win for every time I heard "Now it's Shulk time.", "I'm really feeling it!", "Falcon Punch/Kick!", "Show me your moves!", "Aether!" or even the occasional "I fight for my friends.", I'd be ZeRo or something (-and, psst, I usually do get a win when I hear any of these. Just not... Y'know, literally every time, that'd be insane.).