I don't think it would really change anything with the possible exception of team makeup. But in general GC contenders can not sprint as fast as sprinter so they will not beat them. And sprinters can not climb so the would still not make it to GC. Robbie McEwen won the green jersey last year and finished almost 3 hours down so 2 minutes for 10 stages would not change anythings. The biggest potentail change is that every GC team would bring a sprinter to simply take the time such that the other GC contenders would not get it. But I don't believe it would not change a thing.