I ship Hiccstrid, though I am jumping on the bandwagon of them growing into their relationship naturally, as they mutually mature, instead of falling for each other hard during the movie. In the HTTYD AUs that I’ve written, book Hiccup and movie Astrid don’t become a couple because they want different things in life, and book Hiccup has to stop idolizing her and grow up a bit more.
Hiccstrid in the film had to happen for narrative reasons because she was the love interest, and he was the dorky lead to whom we girls and guys can relate. Should there have been more development? Yes, I have to agree. Is it completely terrible? No, because I still love Romantic Flight.
In terms of character, Astrid keeps Hiccup grounded and reminds him of what’s important on Berk, that he could change things if he could change her mind with one dragon ride. She maintains a level head in their scenarios and tries to protect him from stupid decisions.
I was annoyed with how the show glossed over the relationship, however, and didn’t allow Hiccstrid to occur naturally, even when Heather entered the picture as a romantic rival. If they’re taking things slow, because Gobber or Stoick gave the talk or Astrid has become focused on being the best, then that has to be clearer for the viewers.