A slow effect everywhere in the deserts might hurt (might not, I'm no systems expert) us in the lag department. Not to mention, not all deserts are deep sand. However, it wouldn't be bad, kinda cool, in fact, to have the slow effect in a couple of the areas of the desert, where the deep sand might be, sorta like how you only get the slow effect when you actually get into the mucky water in the swamps.... then again, we'd have to add the slow effect to deep snow as well.... by deep I mean in excess of three feet deep. Alos, making the thirst bit speed up would be pretty cool, too. Good thing Cole keeps an average of eight canteens on him at all times... like a walking fish tank....