It takes a teenager to amor this teenager... Really. Take a poll. Dawn didn't appeal to the older crowd... But I don't think she was meant to. Buffy the Vampire Slayer was not created to appeal to a general audience.. It was for everyone. (Sure, mostly girls, but the guys were not excluded from the inner Buffy-loving circle.) So Buffy moved up in life. No más School. That's where Dawn comes in. Those teenage years are the hardest, (or so it seems then, but they're hard as hell.) and Dawn was there to represent that exact universal issue. Sure, her school life was not seen very much, but it was never forgotten on Buffy that everyone has issues at that age, and you're not alone, and tu will get out alive. This is what the older audience didn't take away from that. Obviously, Dawn could be painfully annoying... But that was a obvious representation of teen hormones and confusing feelings! But Dawn grew up to be an extraordinary girl. She had to grow up really fast, and was forced to be mature for her age, whether o not anyone around her knew that. So, I believe Dawn was important in Buffy. 100%
-Laura