Oh, you're right about Morrolan. So maybe his specific importance in that regard is that he's a bridge between the characters (like Vlad and Devera) and also between Dragaerans and Easterners (like Vlad).

Re: the latter: lots of important Easterner/Dragaeran relationships. Apart from all of Vlad's (and I have to pull out one I just realized now, which is that he's an Easterner wielding a Great Weapon with a Dragaeran spirit), there's Zerika/Laszlo and Cawti & Norathar. Vlad Jr. even has a Dragaeran name and an Eastern name.

So, barriers breaking down = breaking the Cycle. I think.