The lower dmg of Nin is what annoyed me raiding, lol
Plus i had always been a caster main. Ninja are always in demand because utility, and Monks are rare indeed.
I was the only mellee in our group last tier (we had me as Nin, Bard, Smn and a blm) so being the only mellee should not be of issue for contribution.
Sadly i do not know enough about Monk to suggest anything other then have a go at Balance Discord.
They have guides up to date and members always willing to help