If you want a proof this fight is overtuned then at some point it starts repeating itself endlessly without any new gimmicks, only draining healers and tank resources for no reason longer than necessary. The wipes I had were not because people were not doing mechanics, it was because healers were OOM (even with Lucid Dreaming and MP Shifts, you can heal only so long).

In short, it's too long.

Boss' HP should be nerfed by 25%, everything else left intact. And you'll still see the same phases cycling a few times.