On normal difficulty (and probably on Heroic as well), his deck is solely made of legendaries. Hogger, Illidan, Millhouse, Dr. Boom, Sylvanas, Baron Geddon, Tinkmaster Overspark, Nat Pagle, Gelbin Mekkatorque, Toshley, Vol'Jin, Sneed's Old Shredder, Al'Akir (whom I lose to when trying to see the entire deck :P)
I'm 100% sure I know what the "That's just crazy" is. My hint is two other non-secret achievements: Hooked (copper), That's loyalty (golden)
It would be kinda wierd and unimaginative, to have 2nd golden achievement for visiting a page for certain number of days in a row, just for more days then the 1st one ... with all other achievements being nicely creative, i dont want to believe that this is it, that would be very disapointing.