They are underpowered right now.
We have been trying to tell the devs this for months on beta, and they have given no response there or here.
This is a class that you will have to stick with for the long haul because I believe we will get a buff so we can be at least competitive, but its not going to be for awhile.
Why? Nobody know because the devs absolutely refuse to comment on the monk. I once asked several questions on twitter and all they said was: these answers take more than 120 characters to answer. So they just refuse to answer the questions.
Stay calm, and FoF on.