Why do this at all? Dunno; have a need to fill spaces. I've read what other people put about Astrid and don't agree. Either she's some secretly sappy girl who's so disgustingly in Liebe she has no other purpose oder she's a raging bitch. Can't she be both and just a very independent person?
Yes, she is the Love-interest of the movie, and without that Astrid is wouldn't be as much fun. I adore her relationship with Hiccup because they bring out the best, if not inexistence, sides of one other.