You cant really replace the actors for Harry, Ron, Hermoine, Draco, Ginny, and a few others.. i tink if they did they would lose a tremendous amount of Fans and lose ticket sales. It would b tragic too!. And they are only about a year older then the charactors they play. If you notice in most prime time TV(Such as The OC, One Tree Hill and other shows) a lot of charactors that play like highschoolers(like 11th and 12th years) are about 24 or 25 years old! that meanes that they are anywhere from 5 to 7 years older than their charactor. I could understand if they are getting over worked but still... its like having another author write the rest of the Harry Potter books... but not that drastic lol