Mac is out.
Mac watches things occassionally.
Mac brews.
These seem to be his 3 main traits. Nr 1 points at him being 'more' at some point, but I don't think we can just toss 2 and 3 overboard. Especially number 3 suggests he must be connected to brewing somehow. Oddly, none of the Grigori/Watchers have an obvious connection to brewing, so far as I can tell (even though this is usually included in ancient lists of 'crafts').
I agree with those 3 things being major Mac things. So I've been back reading the Dresden Files (because I'm bored and I reread all my books if I am and I super randomly decided to start the Dresden files), and I realized that Jim has never mentioned the Egyptian pantheon at all. There is a figure in folklore named Gambrinus, King of Lager Beer. He's supposed to have invented beer and learned the art of brewing from Osiris and Isis. According to some sources, he might have been a giant who was descendant of Noah and was the first mortal to brew beer (which probably explains why makes it sooo good).
Some Bible myths say giants are offspring of angels and humans. So maybe Mac is half-angel and is the actual king of beer?
BTW, Harry's never soulgazed Mac right?