It's physically impossible for Katrina to complete an eyewall replacement cycle before landfall. It's not nearly enough time. Like I said before, for reasons mysterious to me people have this incredibly wrong notion of how long it takes for an eyewall replacement; it's on the order of 18 hours.
Did you hear the officer in the eye of the storm as he spoke to heraldo? He anticipated a beneficial scenerio in the timing of a wall-restructure. Does that make any sense to you? (I know nothing!)