so earlier today I said Dark Sun and Ravenloft are great settings but not really D&D - Dark Sun might be Fate since it's all about shifting conditions and weird talents more than your gear, I wasn't sure about Ravenloft.
Then I realized Spelljammer is not just D&D but 4e. Weird talents and powerful monsters are streamlined to everyone's special action each round and it's vital to know where you are aboard a ship.
@Leucrotta Suddenly imagining Spelljammer captains absolutely FORBIDDING wizards to cast Fireball on board for fear they'll incinerate the sails or the ship... Again.