I don't mind how people are dressed in J class or anywhere, they will dress how they see fit for the occassion. The big thing for me in j class is the desire for less people.
I just get a closed in feeling in J class most days, and with 35 on a 767 it's crowded, I don't care about amenity kits or pre take off drinks, i just find it easier to relax if there are only smaller numbers.
Keep Joan Rivers away!