MCH isn't the only class to struggle with ping.

Ninja can struggle to, due to the 0.5 sec mudra (even if it was worse before being a GCD), leading to a bunny.

RPR also got a 1.5 GCD rotation with five hit and oGCD in between. Latency can be an issue here again

Red Mage got a fast combo (especially the 3 first hit) that goes slower the further you go in it, but it can still delay the use of oGCD because of Latency in order to no clip it. Minor Issue for this one, but still there.

Also, any class that need to double weave will suffer from Ping Issue (Depending on how high the ping is, of course), making rotation clip.