You guys. I've figured it all out. You'll all think I'm crazy but this is gonna be it.
Luna new year is cantha themed.... in EoD were going to Cantha... The moon controls the ocean... the DSD is actually the deep space dragon! The deep sea dragon is actually the moon! This is gonna be some Majora's Mask meets Dalamud style stuff in EoD! Even the one image of the DSD that is as close to cannon as we've gotten so far looked more like it was in a nebula then water! It all makes sense! This is gonna be where they connect all the dots with the weird connection to stars they have been hinting to since the death of zaithan(the stars that vanish in the orr telescope after dragons die). What possible other story thread could there be that as the dev's put it "has been building up to all along" There are also other hints like how the jade sea vocally in mandarin means Cape of Stars. Cantha also had a lot of random things with the word celestial in the names like the celestial sigil, celestial ministry, celestial calendar, etc. As well as just outright the celestial creatures and weapons themselves added in factions. The Cantha version of ascension is called weh no su which means "getting closer to the stars" If there ever was a time to do the story about the stars they have been hinting at this would be the time to do it.
Also If the second domain for the DSD was gravity it would explain having floating fish enemies on land and water lifting up out of the sea and stuff to make DSD minions a threat anywhere.
EDIT: If anyone isn't familiar with the references to the stars in gw2. I recommend checking out an old video by wooden potatoes. he goes over most references.