Monk's damage is in a pretty good spot, the only thing that makes it's damage seem weak is Ninja being way to strong for how much support it brings (IE:all of the support). It's real issue is that so many of it's new abilities all just feel like crap to use on some level that it's taken a Job who's claim to fame was "It's streamlined, it's fast and it just feels good to use" and made it "it's streamlined but it's completely stale having been doing the same thing for so long, and now its kinda janky and gross to play."
Brotherhood is good on paper, but it also makes Monk highly party composition dependent for both personal damage and overall party contribution. If you have a caster heavy composition in an 8-man or don't have a Warrior tanking and Bard/Machinist in 4-man's then it hurts your damage pretty substantially.
Riddle of Fire boosts your damage to wacky levels, but it eliminates your speed buff which was basically the main draw of the job since ARR. If I don't have an Arrow I pretty much despise using it even though it makes me hit for huge amounts of damage.
Riddle of Earth is just ability bloat. They could have reduced Perfect Balance's cooldown time to a better effect, because as it is this requires you to get hit within the window for Greased Lightning in order to work. If the boss jumps and doesn't do damage like he does during Susano's first jump? Tough luck and Perfect balance is still on cooldown. The same is true for older mechanics like Time Gates, A11 Quick Time events, and stuff like Gaol's.
Tackle Mastery is just dumb. Why did they think it was a good idea? We will never know.
The fact that they said they considered Greased Lightning IV is a total bummer too, because I would have liked that as a cooldown more than anything we got.