I might not be the first person to notice this, but is the dragon deal in Mor Dhona the fight from the opening cinematic? I have placed the images side by side for comparison
If so, I wonder why there is water everywhere in the video and Mor Dhona appears to be landlocked...
The similarity to the Mor Dhona Dragon/ship and the footage int he trailer was first mentioned in this thread on Mor Dhona
. There is also quite a bit of discussion and analysis of the different parts of the trailer in the thread announcing the new video - New "trailer", official opening movie
. The dragon/ship similarity was then again brought up in this thread - Research after seeing the Trailer
. The most recent trailer/dragon/airship discussion is on this thread Do garleans control the dragons or the airships?
As to your question as to why there is water in the video while the area is landlocked is because the airship crashed into a lake, not a sea. That, and the fact (mentioned in the last thread I linked to) that the event that the character in the trailer flashed back to was from 15 yeas ago, it could be assumed that there has been some changes to the terrain in that time as a result of the crash.