As usual, Snarf's OP is fantastic - I love both the time capsule visit and the overall assessment of the underlying issues, which I think have always come down to D&D not knowing quite what to do with the class.
That said, a number of us have been tossing around ideas over on the OneD&D forum, and here is my consolidation of them into a few very minor tweaks to the current UA that I think would hugely benefit how the class plays. Alterations in italics:
I read that thread, and as you might tell from the OP, it informed some of what I wrote. I think people are doing good work in there! Well, despite the occasional sniping that is part and parcel of life on the 'tubez.
That said ... (you knew it was coming!) the thing I've been thinking about, and the genesis of the thread, was when I was thinking about my feelings about the monk, and why these changes felt especially off to me. And I think it's for two reasons.
The first is that some of proposed changes genuinely don't make sense to me, especially in light of the increased emphasis on "buffing" martials (with Weapon Properties, no less). It made me think about how the whiteroom combat theory about the Monk tends to get a lot of things wrong, and the original sin is that it tends to overvalue weaponless combat and undervalue the inability to use magic weapons or magic armor - and how MAD the Monk is compared to other martials.
Second, and more important, was the realization that the changes were really all about combat. And I think that's where I really started dwelling on the problem with the class, which is a little different than most of what is written. As I wrote, I love the monk. It's a fun and different martial character to play. But here's the thing- there's already a better fighter (the, um, fighter). There's a better tank (the barbarian). There's two classes that are both martial and a lot more versatile (Rangers and Paladins). And there's even a class that does better surge damage with out-of-combat utility (the Rogue).
And that's when I realized what the real issue is. It's not combat, or, not mainly combat. The monk will always have a great niche as the fun, mobile, squishy melee character. The problem is that the monk is being completely combat-focused.
Think about it- it's both MAD and often dumps charisma, so your Monk will usually be the last choice for any social interaction.
The Monk (unlike Rogues, Bards, Artificers, and even Tasha's Rangers) doesn't have expertise as an option, so it won't ever be great at skills.
Because the Monk is MAD, and needs high wisdom and dexterity just for AC, it is hard to justify feats; moreover, most don't help the Monk greatly (unlike some of the weapons feats).
Heck, the Monk is a class with a super high dexterity, yet almost exclusively uses melee combat (which circles around to the issues with hit points and AC).
I've played a lot of Monks, and they can be fun at combat, but they often twiddle their thumbs at everything else. Even things they should be good at (like scouting) they will often take a backseat to classes like the Rogue with expertise. The UA simply confirms and increases this trend by orienting them even more towards combat, but continuing to make them the designated second-class martials.
Which is fine. Monks don't have to "outfight" the fighter. But they have to do something. Heck, even basic things like the fact that most Monks suck at athletics is kind of a kick in the cojones when you're playing them.
Given Monks cool abilities. Give them more ribbons. Instead of worrying about their combat (which is ... fine) let the Monk get some skill certainty, whether through expertise or fixed abilities. As far as combat abilities go, and with the new ki ("di") regeneration, the combat abilities of the Monk are fine, albeit with the need of some tweaking. I'd like to see some thought put into fixing the other aspects of the Monk that are glaringly obvious in play- everything from "why do Monks suck at athletics," to "What are Monks supposed to do in real campaigns when other party members are using magic swords and magic armor and feats to be all awesome while the Monk is still stuck at the whiteroom theory level of DPR?"
so there is this netflix series that season 2 just dropped a little while ago called "Warrior Nun" and the main character gets super powers but her sisters are all just what we would call monks in D&D.
people tend to forget monks having d4 because they could dodge so well. If you got them to 6th level or higher they were they were the ultimate mobility and avoidance class. If you ever got to stunning blow and quivering palm they became scary scary things. But that was how 1e was. The classes that sucked the most at lower levels became really powerful at higher levels. Monks with thier avoidance ability tended to live longer than mages at lower level.
I would argue that batman in the Animated Versions is a rogue....and I think that's part of the problem.
The modern identity issue of the monk in 5e is its a rogue wannabe more than a fighter wannabe. The monk is fast....but the rogue can bonus action dash at will. The monk is evasive, except the rogue gets evasion AND uncanny dodge. The monk is acrobatic, but a rogue with expertise is more so.
In terms of the core "ninja esque martial arts guy".... the rogue just does it better. So to differentiate, the monk should go Wuxia. It should be completely mystical, and yes in 5e terms that means it probably shoudl have more spells (I know some people hate that but that's how 5e does the job).
If you want to play a more grounded martial arts, play a rogue or a fighter. Give them unarmed strike as a ribbon and your good to go. A monk should be the anime esque Wuxia motiff, because right now its just a badly watered down rogue.
In most versions he can fight, but is far more important for looking after the outlaws spiritual welfare, since they would have believed that not receiving communion damaged their immortal souls. Note, although he is a monk, he is also a priest.