I'd like to see him pull off another startup and grow it to be as big as Reddit is, then everyone would know it wasn't just luck and would have much more confidence in him.
As an angel investor, what is he bringing to the table? He has some experience with startups but not a whole lot. He was a non-technical co-founder and spent most of his time using Reddit like any other user. He didn't do any coding, scaling, or sysadmin work. Reddit isn't even profitable.
He did draw the Reddit alien though...