The E is a logo, not a mascot. Mascots tend to be people, animals, or some manner of character in general. And not "character" like letter you wise-mouths.
There is a great deal more on this site than ZP, and regardless of it's contributions to the site it should not be the only thing represented by the mascot. There's a great writing staff, as well as several other video series that are well worth watching. Saying we should use the imp because ZP is huge is like saying the US should have stuck with the union flag because it was those thirteen states that declared independence and the rest were just hangers-on. You've almost got a point, but you're also wrong. That being said, I've got nothing.