Doesn't longer hair make the guys in HP look good?

[ish_starbabe]

I think most of us would agree that Harry,Ron and Draco(Dan,Rupert and 
Tom) look good with grown hair.That makes them attractive on screen as 
well as in reality,so instead of cutting their hair they should have 
trimmed it.
Also i think Harry(Daniel) was supposed to have long hair in the movie 
when a whole lot of witches and wizards come to fetch him in the 
beginning of OotP....so why don't the moviemakers stick to that or is 
it that the actors don't stick to that.
Even Hermoine(Emma) is supposed to have curly brown hair but it just 
seems to keep on straightening as movies are coming forth!!!What is 
the possible reason for this?(this does not include the yule ball in 
Goblet of Fire cause she is supposed to have a different hairstyle!)