I wouldn't get my hopes up on SE adding new skills anytime soon; they had their chance already and failed miserably. Altering the skills we currently have would be the best bet, even if that won't be enough to fix all the issues with MNK, such as the several odd skills that serve no real purpose other than to be button bloat (Fist Stances, One-Ill Conceived Punch, etc.)
That being the case, I am greatly hoping that SE sees reason and alters a lot of MNKs current toolkit because it's a disjointed mess.
For starters, Riddle of Earth needs to be reworked to provide the extra mitigation upon activation instead of on being hit. The mitigation buff is completely worthless AFTER taking substantial damage and since the majority of players would immediately reapply FoF after the hit is over, it sees no real use either. The GL refresh has situational use but at the same time it encourages bad play habits by making players WANT to be damage to maintain their buff and that's not a good habit to enforce on any class, much less a DPS. If anything, I would like this to double the max duration of GL upon activation, instead of when damage was taken. It would serve the same function without the negative effect of encouraging taking needless damage.
One Ilm Punch and Arm of the Destroyer need so many improvements. Situational effects are terrible enough as is but to add to this is the problem that these effect can only occur during very specific moments in our rotation (correct form) and they become borderline useless. Remove the stun and silence from each of these skills. Up the potency of AotD so that it's just a flat out damaging AoE that is actually useful and add a DoT to One Ilm Punch to make it actually worth using and keeping up (reduce the TP cost as well since it shouldn't be needed now that the skill is going to be included in a standard rotation instead of a situational one).
Return the Stun to Steel Peak.
Tornado kick needs to do more than be just a big attack that we use whenever mechanics dictate we are going to lose GL anyways. It's in direct contention with Riddle of Earth in how we use our GL and as such, I feel I could live with Tornado Kick being more of MNKs raid utility by adding vulnerability or reducing the damage the target does. Extend the cooldown of TK to 90 seconds if you need to to prevent abuse but I really feel that if MNK needs to throw away a large portion of their damage on a single attack, that attack should be worth more than just a simple damaging attack.
Purification should be altered to provide 100 TP per chakra. While MNK isn't TP starved anymore, with my suggested changes for One Ilm Punch, it might not be a bad idea to maintain the TP restore of this skill, just as a precaution.
Riddle of Fire needs the slow effect gone, even if it meant lowering the potency of the buff. It goes against everything that has been established for MNK as a fighter that hits fast, not hard. It just doesn't fit into the theme of MNK at all and needs to be changed.
I want to know who gave the ok for Brotherhood to go out as it was because I want to slap them. A 5% damage buff that occurs once every minute or so that only affects physical damage, not including the MNK themselves, vs an AoE balance that grants a 10% damage buff to ALL damage and affects the AST that cast it as well. This is why MNK lost the majority of it's damage for? A shittier version of Balance? Really? Come on SE. Including everyone in the skill to gain 5% more damage is not going to break the game.
Tackle Mastery. Delete it. It's a pointless trait that should have never been conceived in the 1st place. I'd honestly take a CD reduction passive whenever a Riddle is activated over what Tackle mastery currently offers even if it was still a terrible passive but at least it would be more practical than what it currently is. I mean honestly, a knockback? On a Gap Closer? On a Class without a single ranged attack whatsoever? WTF were you think SE?