Only wildcard I can see is that upper low over the western Gulf that could start to tug a bit on Dean - on the water vapor GOES loop, it seemed like Dean was starting to elongate just a bit to the N-S - a slight right turn would put the storm squarly in monkeyland and north of Chetumal (placing them on the weaker side of the storm, lucky for them if that happens).
Just not TOO much of a right turn for Cozumel's sake.