I don't think synesthesia means anything other than that your senses haven't seperated properly, at least that's the basic physiological explanation. I think people are very curious about it, maybe because it feels like you have access to something others don't. But, like perfect pitch, you certainly don't need to have any of these slightly rare conditions to write great music. I think musicians are always concerned that others have more access to 'music', either through notions of talent, physiological differences, such as synesthesia and perfect pitch. And I think that the idea of these things having any bearing on your musical fruition are largely romanticised (....I'm sure Undershadow's ear just pricked up). In other words, you write what you write, despite who you are and what goes through your mind.