The Good
The core form based GCD loop is just as satisfying as it has always been. It hasn't done anything new, but that's for the best because it has a very distinct gameplay feel and it's the biggest part of what makes Monk tick.
Perfect Balance and Masterful Blitzes are fun new additions to the kit and there's ample room to develop on them in future expansions. Rising Phoenix and Phantom Rush are both badass and feel great to use.
Thunderclap is a great replacement for Shoulder Tackle. Not only was it a serious issue needing to dump Shoulder Tackle in damage windows, but Thunderclap as a movement skill has a claim to being the best movement skill in the game with its long range, low cooldown, and three charges. It is a welcome change from Monk having the absolute worst movement kit in the game in previous expansions.
The Meh
Riddle of Wind exists. You hit it every 90 seconds but it's a button that feels like it has no effect at all when you press it. Auto-attacks are basically nothing as far as gameplay feel to me.
Six Sided Star is useful as a downtime skill, but it's pretty sad as your Shadowbringers capstone skill for the same reason everyone complained about Shoha so much. It's a downtime skill you want to minimize use of whereas people usually want their capstone to be a skill they use regularly that has some oomph behind it. This is doubly an issue when it arguably competes with functionality with Meditate.
Riddle of Earth is a strong defensive option that you can use so often that it may as well be a 20% defense up trait for raidwides and targeted mechanics. However it still has the awkward three weaponskill duration from when it nullified positionals.
The Bad
Chakra (still) for pretty much the same reason that people talked about in Shadowbringers. The inability to use it without it being capped and the fact that it builds randomly is design that is inherently at odds with itself, and it's compounded by Monk having the fastest GCD recast because you have shorter windows with which to use it should you cap. I personally just hate that they're RNG at all, but there's still plenty of changes you could make that keeps the RNG crit effect that currently exists.
Anatman... it exists, but it basically doesn't justify its own existence. It doesn't even extend the timer of Leaden Bootshine. The addition of this was one of the most poorly conceived decisions in the history of the game and there's really not much that can be done to fix it without completely retooling it into a new skill.
There's also an issue with dated animations in general. A lot of Monk's older skills don't really mesh with the current speed the job operates at or don't really mesh with having a changed role in the kit. Just to list a few; Bootshine with Leaden Bootshine lacks the impact it should have now that it's basically Monk's standard combo finisher. True Strike and Snap Punch are actual martial arts moves that end up looking janky in Monk's increasingly anime-looking kit. Elixir Field looks slow and awkward after being turned into a Weaponskill from an oGCD. Flint Strike also is pretty low impact, but it gets upgraded so it's not really an issue.
So what should they do
Riddle of Wind and Six Sided Star can fix each other IMO. Riddle of Wind and Six Sided Star can continue to exist as they currently do, but there should be an additional trait added when you unlock Six Sided Star. At that point you should also get the trait "Enhanced Riddle of Wind" which gives you one stack of a status called "Rolling Cyclone" or some such, that halves the recast of the next Six Sided Star (meaning it would have a normal GCD). Riddle of Wind gains more impact, Six Sided Star gets rotational use and it can still be used for disconnects. Win-win.
Riddle of Earth should have the weaponskill requirement removed and it should last for like 6-7 seconds, nothing complicated there.
Chakra has a world of options, the earlier suggestions in the thread where it works somewhat like Pitch Perfect are perfectly good fixes. It could also be given a cap of 10 with Forbidden Chakra/Enlightenment can be fired off at 5 as it is now. I'd personally like to see Chakras open on Coeurl form skills and for Brotherhood to be reworked so it isn't RNG at all. All options are viable as long as we can get out of overcap hell.
Anatman is probably unfixable if we're being honest. Monk already has three downtime skills in Form Shift, Meditation, and 6SS, it doesn't need one that prevents it from taking other actions exclusively to upkeep Disciplined Fist.