Given this appearance on MW imagery, I don't think an eyewall replacement cycle is likely for at least another 12-18 hours:

It has some of the makings of an outer eyewall, but lacks the closed structure to one, suggesting that a significant eyewall replacement isn't likely in the short term. Plus, Dean is moving toward a region even more favorable from a heat potential standpoint:

If it stays far enough south of Hispaniola, things could get pretty interesting as it nears that warm eddy. Of course, by then, it might be in the midst of an eyewall replacement cycle...only time will tell.