Iridikron and Xal’atath sowing chaos underground could mark the beginning of the return of the Eyes of the Earth-Mother. I believe the conspicuous absence of Elune and An’she was caused by Titan machines. If they were destroyed or damaged, it would weaken the Titans’ grip on Azeroth, but at the same time, it would other powerful forces from access Azeroth. I don’t believe Elune and An’she were imprisoned by the Titans; rather, they simply had severely limited access to Azeroth.
Personally, I suspect that Eonar is a Titan who has been taken over by the forces of Life; that’s why she has such a strong connection to Elune. I wrote about this in more detail here.