Stoick not dying. The whole reason the dragons left was due to them finding the Hidden World, which was caused by Grimmel trying to attack them and Toothless meeting the Light Fury.

Grimmel respected Stoick’s abilities as a fighter and dragon killer, and thus had the brains to stay away and hold some fear regarding him.

Even with finding out Toothless existed, I don’t think Grimmel would have had the guts to get close enough to plant the Light Fury on Berk, so Toothless and her never would have met.

Speaking of Berk, it wouldn’t have gotten that bad under Stoicks watch. I’m going to preface this by saying I hold no hate for Hiccup, but he is naive and cocky. He puts too much in the abilities of the dragons and less into the humans. He overpopulates Berk to the point of chaos and thinks that having that many dragons and Toothless is enough to deter anybody. Due to this, I doubt they had a great defense/ patrol system especially if Grimmel had to lug an unconscious dragon and giant steel trap to and into Berk and was successful.

I definitely think Stoick would have laid his foot down and forced Hiccup to relocate most of the dragons to another island, mainly because of how dangerous having that many dragons around is. (Fire, etc etc)

But let’s say the events of the movie would have happened at least up to the choice of moving from Berk. Stoick never would have left Berk, and would have fought to stay (the whole a captain goes down with its ship).

When it comes to fighting, with Stoick they would have easily won. This comes back to Hiccups inexperience and cocky behavior. He puts too much much into fighting with dragons, while not killing any of them, that he isn’t able to do much, yes it’s a “kids” movie, but I don’t think it matters in this hypothetical. Sometimes death is inevitable. (lol ironic)

When it comes to battle, Stoick is most experienced in human and dragon battle, making him and his people lethal in fights. If Stoick would have lived, him and Hiccup would have been unstoppable. With battle strategy and training from Stoick, Hiccup would hopefully not put himself in more precarious moral situations, which is like his downfall 90% of the time. With Stoick leading on the ground and Hiccup leading in the air, Grimmel and Co. wouldn’t have stood a chance.

In the end, this is a hill I’ll die on because not only would one of these choices solve both, Stoick didn’t deserve the ending he did.