Yoshida mentioned somewhere that the original main storyline would continue in 2.0 once the 7th Umbral Era storyline had run its course. Although honestly, I have no idea how that will work. Sure, all of the original main storyline quests are going to be reworked, since they are throwing out the "one storyline for battle classes, crafters, and gatherers" concept (thank God). But all of the environments are going to be different, so they are REALLY going to have to alter the main story missions to make it work.

Maybe the Mor Dhona dragon will stay in 2.0? I don't know. I will say this, though: I find it really odd that no NPC in the game now ever seems to talk about it. I mean, it's a mammoth, freaky-looking dragon corpse wrapped around the remains of a giant crashed airship. You'd THINK it would come up in conversation every now and then.