I don't like the decision that the new allied races can't be monks. It doesn't make much sense, as it's something that can be learned. There are monk trainers scattered across Azeroth now. It's not like a Death Knight, where it's technically in the past. Theoretically any new race can 'choose' to pick up the ways of being a monk.
What I'm trying to say is that Zandalari should be able to be monks. Any new race should be able to.
If they can become warriors, they can become monks too.