All I can say is you have no idea what you're talking about.
I'm not basing anything off of dummy parses. It is far too easy to outparse other jobs on a dummy. Training dummies are good for testing a DPS ceiling. However, MNK is designed with such amazing DPS at GL3 because it is expected to lose the buff due to mechanics in content.
People keep complaining about GL loss and blaming it for their performance not measuring up, or they simply can't parse worth a damn. I don't know why. What I do know is, even with a reasonable amount of GL3 loss, MNK is top. The reason is, you only need to know your optimal rotation and maximize your GL3 uptime. That's it.
I go as MNK to both Turn 4 and Turn 5. I have regularly topped parses in turn 5 with very capable and equivalently geared BLMs and BRDs in party. Heck, even with a BLM using level 3 LB on all 5 snakes in Turn 5 I was higher, though barely (no LBs myself). Of course, you can elect not to take my word on it and chock it up as personal experience. However, no. You are wrong.
Our job is not perfect. No job is. However our job is indeed balanced. This should be good news to you, because unlike actual weak jobs that need buffs like WAR and DRG, MNK as a job is fine so all you have to do is figure out how to perform better if you are somehow not putting out dps competitive with your BLM and especially BRD buddies lol.
Also, again - get your facts straight. SE is not increasing melee damage in 2.1. They are tweaking content so that melee DPS jobs are not as punished. Basically, they are making it easier for more people to manage to keep their buffs and stay on the enemies longer when on melee jobs because - no surprise - a lot of people on melee jobs suck at it.
tl;dr: MNK is a high risk - high reward type job that has an incredibly high DPS ceiling, and as such is designed so that it is incapable of maintaining it in competitive content. If you mess up, you do horrible DPS. If you play well, you do amazing DPS. You clearly don't know the job very well if you mean to suggest we should be able to stay in GL3 all the time lol...