completely broken, virtually non-existent resting mechanics (D&D is wholly balanced around it)
overpowered bonuses for height and flanking
Not many mentions pickpocketing as part of the cheese, but it very much is.
Consider "weapon dipping".
Much of the same criticism can be directed towards the "shove" or "throw enemy"-mechanics.
Why aren't the enemies reacting to explosives in their midst?
Over-emphasis on homebrew/cheesy magical items.
Once you move beyond the "if you don't like it, don't use it"-mindset and actually bother to analyze the issues, you realize this is about much more than a handful of easily ignored implementations. BG3 is supposed to live up to the legendary title, but Larian is dropping the ball gameplay-wise. Larian could give us their fun gameplay elements without sacrificing balance and immersion, just by respecting D&D a little more. Larian (writers AND programmers) and Wizards of the Coast (D&D experts) could benefit immensely from a sit down focusing on making the gameplay congruent with the 5e setting and BG3 story.
These are all great examples of major balancing problems im BG3. It is frustrating to hear so many apparently ignorant people say things like "play another game then." The point of this forum is to discuss the game, and Larian has explicitly asked us to criticize the game so they can make a better one.
There are major issues with the way the game mechanics are balanced. Not just between classes, but the way D&D has been refined and balanced over five decades. This is not some silly generic RPG -- this is an officially licensed campaign. So, if you give players unlimited shove to CC every fight with no skills or spells, easy advantage on all attacks, consequence-free stealing of all items and gold, effortless cheesing of AI through barrels, and unlimited replenishment of spell slots and abilities...then it's not D&D anymore. The game mechanics are what define the game. Removing all the game mechanics makes it not the game.