Just did this boss on the PTR. At least our tank was overgeared (full 378; items that drop in the instance are also 378), I don't now about the others, I had to use an old character (copied durign 4.2 PTR) because character copy doesn't work in europe.
The video (just uploaded it, might not be available (in HQ) yet):
http://www.youtube.com/watch?v=D76MYv20unc
At the moment, he is - imo - way too easy. He either needs more health or the number of times you can rewind time should be reduced to 4 or 3.
Also, the instance feels too easy as a whole. I only killed Jaina (as the first boss was already killed), but she (and Sylvanas I saw) had only 5 millionen health - the Zandalari bosses have 5 millionen or more health, that just seems off. The trash was also strange - Jaina had trashgroups consisting of 5 mobs with 700k HP average, Murozond's trash only consisted of 4 mobs with 300k to 400k life. Oh well. I hope this will be buffed a bit. But it's the first day, so yeah. As the Zandalari dungeons have also been buffed, I am optimistic.