Well it's still early, and I haven't been hyper-analyzing him, so "in-depth" right now isn't much more. That was my nice way of saying "I'm too lazy to type anymore," lol.
Buuuut, since you asked, I suppose I can say what I think makes him cool. Mostly it's just I like what he symbolizes to the guild. He's the powerful and reliable one, sort of the one you can trust to "save the day" if all the other (our characters) mages can't quite step up. The personality you gave him is why I can say "reliable" and "trust" because he's too nice to sit by and do nothing. He actually cares about the guild, unlike someone like Laxus early in the manga.
He's older, smarter, and "chill" without being indifferent. He's lively without being over the top, which would kill any sense of maturity you'd expect in an older character. He's got all the qualities needed to fit his role, be likable and interesting, and yet not seem like three personalities haphazardly rolled into one.
Now that I've said all this nice stuff about him, try not to f*** it up. No pressure :D
