I still stand by analysis that playing a Monk is much more complex that it first seemed and that, in that way, it's a newbie trap. If you play too aggressively at the wrong moment you get punished because your AC and HP are below average for some who should be in melee, and if you play too defensively at the wrong moment you end up just prolonging the fight and feeling like you're just standing there. But for all that difficulty it doesn't feel like you're rewarded with performance that are worth the effort.
It's also too MAD so you always end up with the same three stats of DEX, WIS and then some CON.
I can say, that the monk from level 2 and up to level 9, they have no problem at all to keep up.
Without ki, at level 5 they have 3 heavy hitting attacks, 1d8+4/1d8+4/1d6+4 is not bad at all. They are fast as hell and can get onto the enemy face. With the upgrade in tasha, they can easily have 1d10+4, 1d10+4, 1d6 + 4 (avg 26)
Compare that to the rogue's
5d6+4 (avg 22.5) at that point.
The rogue often has advantage and can uncanny dodge defensively. The monk has stunning attack often enough, which also results in advantage and has deflect missiles (at will) .
AC for both is 16 or 17.
The rogue is always ready, the monk needs short rests.
The rogue get higher sneak attack every 2 levels. The monk gets 2 ki points per 2 levels, which makes their life way easier. Each ki point if used on flurry will add 1d6+4. Dex 20 will increase damage more.
So lets do a resume: the monk at levels 1 to 9 can easily keep up with the rogue who at level 1 also does not have much to protect them. The rogue has expertise which is nice but does not make the rogue so much better. The rogue has more freedom to buff constitution, which might result in slightly higher hp, but at lower levels we probably speak about 1 hp/level = 1 to 9.
With tasha, the monk can convert spare ki to hp.
Levels 10 to 20 makes the monk fall of a bit I guess, but most classes don't progress properly at that level. Monks get a lot tougher as barbarians. Even the much praised fighter does not gain much offense after level 11, so in the end the monk does not look too bad.
I think a little buff for defense is in order. d10 or even d12 HD would nicely help.
I guess in 5.5 recharge on a short rest will be gone. I do strongly expect many abilities on a prof bonus per long rest timer and maybe a pool of KI for the rest.