It's not that the tech wasn't there, it's that they didn't want to spend the time to make a new 5 headed rig for the model, so they created Ultraxion instead.
Cata was an expansion that stretched all teams very thin, saw tons of cut content, cut corners, and slapdashery. Then behind the scenes they were also working on Mists of Pandaria.
These are the same devs who have overused the Gronnling skeleton so much people are sick of seeing it after only a couple expansions.
Speculation:
Chromatus is important not only because it is a dragon, a Nefarian experiment on combining the dragonflights, but also because it was arduous to bring life to him.
The Dragonflight leak talks about: Uldaz. Second fully underground zone ever on Azeroth. Titan/Elune story here. Maybe Galakrond was infused with life, and it was a failed attempt to elevate protodragons by Elune. My point is, maybe, there is a connection between Galakrond/Elune/Titans.
Also, the Old Gods were crucial for Chromatus existence.
In this sense, maybe the expansion starts with some Order Halls, but other order halls like the Dreamgrove step in if they go to Uldaz.
IF, in addition, we need the dragon isles to heal the world, Alexstrasza seems the obvious choice to guide us into life and dragon-centered expansion.
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I insist I would like a Quelthalas warfront where we defend the city against undead waves. Maybe a challenge mode of infinite waves.
Yes my child:
https://pbs.twimg.com/media/FPZ1PZTX...pg&name=medium
Popped up on Reddit I believe