Originally Posted by Brainer
I do have to save-scum a lot, though, mostly for trying to get crowd control to work so that enemies don't overwhelm the team. Having a monk with stunning strike (which can stun everything, from undead to golems, apparently? Huh) really helps, and makes me confused as to why people think that monk is the weakest class in 5e. You no longer need strength like you did in 3/3.5e, you can make 4 attacks per turn at level 5, and while the damage isn't too high, it does get decent eventually. Re-rolling until both dexterity and wisdom were at 18 also gives him 18 AC right off the bat.
I mean, you kind of give the reason in your first and last sentences. I'm not sure if your save-scumming extends to Monk Stunning Strike, but if so...that's a huge boost in power. And most players don't get to reroll ability scores to start with 18s in Dex and Wis for an 18 AC.

A typical monk will start with, maybe, Dex 16, Wis 16, Con 14. Quite likely one of those will be lower by 2 points. This means a 15-16 AC -> you'll be hit ~30% more often. An additional point in your Wis mod means your save DC's are higher too.
Stunning Strike is against Con STs, which monsters are typically the best at. Add in Legendary Resistances, limited Stun immunities, and limited Ki points at levels 5-8, it becomes much weaker. Imo, Monks only become really good at levels 10+, when they can Stunning Strike multiple times each turn, for multiple turns in a row, while also using some Ki for other abilities.

Finally, Solasta is very generous with its magic items, enabling Monks to get even better AC, damage, etc. Also, I haven't done an exact analysis, but most homebrew subclasses in Solasta are OP, so your experience might vastly vary depending on your chosen subclass.

Originally Posted by Brainer
Big bonuses to enemy rolls (+3 to everything) also showcase how flat 5e's combat can become when >90% of the ways you can affect your or enemy's accuracy are advantage/disadvantage-related. Disadvantage tends not to do jack when the enemy has something like +13 to hit, and attacks 2-3 times on their turn. It does make the AI change priorities in combat, so you can artificially make them target somebody with a lot of AC by using/giving Dodge to somebody with less. Speaking of Dodge - could it be that the monk is the last class to be introduced in BG3 because we have no Dodge yet? It's one less ki power if it doesn't exist.
Yup. The Advantage system is balanced assuming a ~25-75% chance to-hit. Beyond those bounds, it's effectiveness is much reduced.

I mostly dislike that dodge-AI interaction in Solasta. Usually if I'm dodging, I want the enemy to attack that character, because now they'll be able to tank better.

Possibly, but Dodge should be nearly-trivial to implement, so I doubt that's the main reason. I suspect Larian wanted to finish their reaction system before implementing monks, as monks have many things they can do as psuedo-reactions.