Dawson is VERY accurate, he throws lots of fast combination's to A) win points and B) beat down his opponents. Dawson is always in position to never be caught with a counter-punch, he just doesn't randomly throw flashy combination's.
Hopkins is slick enough to give Dawson problems but I see Dawson's speed, workrate and agility as the deciding factor. Hopkins looks great against slow footed fighters like Tarver and Pavlik but Dawson would win on points.