Thinking about Httyd again and because I sort of managed to think up a really good Rott alternative, I'm tempted to try for Httyd3 as well. However, rewriting Httyd3 first requires rewriting Httyd2, and I'm just not up for that.
Quick thought for Httyd3: What if the LIGHT FURY was actually the most rare, sought after dragon of the Archipelago, and not Toothless??? Where Grimmel as an expert hunter is actually able and willing to trade Hiccup tips and tricks on how to track down more Night Furies, leaving Hiccup to need his enemy???
What if Toothless goes to the Hidden World for the sake of the white dragon's safety and not because of his own. Were it for himself only, he'd stay by Hiccup's side until the end. But for the girl??? Hiccup couldn't say No, he would support it!!! And there could still be more Night Furies??? The story wouldn't leave such a bitter aftertaste??? Because what if she could actually be worth it???
Think about how this would shift the narrative!!! Hiccup and Toothless would be the center of the plot in a far different, more selfless way. And they would still be friends instead of facing a divide of loyalty. She could be painted as worth saving.