MNK 50-60 is a pain in the ass for a lot of reasons:
1) Crabs. Crabs, crabs, crabs, crabs, crabs. Sure, you CAN level off of Bones and other stuff, but just try to get people to go to Garlaige/Gustav.
2) As above, crabs. But now it's because you can't do Distortion until Howling Fist, and every goddamn party wants it. Never mind that we can close Impaction with Raging Fists, and crabs are weak to Thunder... everyone wants to MB Freeze, so you're screwed.
3) More expensive equipment. Thought you were done with the 1M Kote, 900k Brown Belt, 400k Jujitsu Gi, etc? Heh. Say hello to 3-5M Cross-Counters (or 1M for the 'gimped' Spartan Cesti,) 4-5 million for Scorpion Harness, and another 1M for Kung Fu Shoes (if you want 'em) and 4M for Spectacles. Hope you found a good farming spot.
4) People on their second/third/fourth jobs are taking to Monk like a fat kid to a Snickers, so you have to compete with other MNKs that already have all this expensive gear.
So yeah MNK 50-60 is rough, but I plan to get through it once I heal and I know you can too.