The best thing about the MNK is that the core rotation DIDN'T change in HW.

For NIN, they added a new skill that allows them to refresh Huton without actually casting it through Ninjutsu, letting them use Ninjustu for more attacks, one of them being a new 3 Mudra attack. Great and dandy, but if you have bad latency, this is actually going to be a DPS decrease because you won't be able to fit those new attacks in between normal rotation skills.

And the DRG, oh my. Ok, Imagine a MNK, right? Now imagine if all your positionals were COMPLETELY RANDOMIZED. They literately added two new mechanics to the DRG, one is a randomized positional, and the other is a resource management. Awesome.