I have seen both 1 and 2, but how will the third one turn out? The dragons going away from berk? Drago Bloodvist returns?
With the third ones release date in 2018, they have plenty of time to think of the story. Here are my thoughts, on the ideas listed above.
Dragons Going Away
If the dragons go away, then the Vikings on Berk will freak, and Hiccup might go on a search for Toothless and the rest of the dragons.
The dragons would go away, and they would have to find them to beat the rest of Drago's army from How to Train Your Dragon 2.
If the previous idea does happen, then what that mean if Drago comes back?
Hiccup searches for dragons
If Drago comes back and the dragons are gone, Berk will fall. What if Hiccup tries to bring them back to take Drago down for good?
You may be asking this:
He's dead? How would and could they bring him back"
What if a new dragon came with firing its attack could change the past? Maybe Hiccup could use that to bring back his fallen father.