I find leaving Sea World's lot at closing to take much longer than leaving the Disney lots. Getting to the car isn't a problem. Traffic, once you're out of the lot, isn't a big problem. But it does take longer to get out of the lot, in my experience.
I do hang back, walk slow, look around, shop (if anything is open), whatever I can do to kill a little extra time if I'm leaving when it's busy.
I do this at the MK, too. Getting out of the lot is no problem at the MK, but waiting for monorails, busses or boats is a pain. I'd rather walk, shop, etc. than go through that.
Lot-wise, Disney set it up like geniuses. There is no problem getting out. Whoever set that all up deserved an award.