I disagree with the take on Chromie and Dracthyr that some people in this forum have.
First, overexposure of Chromie, really? She got a short story that I bet that most of the playerbase have not read (which was decent, IMO) and some quests in 10.0 (which were cool with Eternus and the time travel stuff). Not much more. She is still a secondary character, and I neither love it or hate It, but she does not have been overexposed.
Second, I understand that people might be dissapointed because we have not get (yet) the bulky Drakonids, but I have to commend Blizzard for having the balls to do something original with the Dracthyr. At least for me, they are something new in a fantasy setting, and I think that they have a lot of potential to be a very interesting addition in the future of Warcraft. We will have to wait and see what is their big secret.
As for the Drakonids, there are several elements in DF that very much point to them eventually becoming an Allied Race IMO.
Finally, now that we know what 10.1.5 is about, I think that the rest of the patch cycle is clear:
10.2 will be about the Green Dragonflight.
10.2.5 will be about the Blue Dragonflight.
10.3 will be about the Red Dragonflight.
The Red Dragonflight has not have practically any development until now. I think that their story would focus on the Dragonflights coming together, fighting the Incarnates / Decay.