Just my 2 cents. Personally I don't really care how they were marketing the game and how D&D 5e accurate the rules should be in general. But I think a quite big portion of people are criticising the homebrew rules and saying that Larian should have a good reason for any changes they implement, and that the changes should make the game better - and i fully agree with this statement.
Based on my understanding of the original D&D rules, the changes made to BG3 EA (and well, based on my experience with Solasta) i have to say im in the camp who would like to see options (or as others said a 5e difficulty mode) to be able to alter/revert some changes. The reason im saying this is not because then it can be a true d&d game or it can be what they said they plan to make (i will leave these arguments for others), i just feel some of the Larian changes made the EA less tactical and less fun for myself and that these are not related to BG3 being a videogame. I completely agree that in a videogame things should be more fluid than in tabletop and hence, changes need to be made but i dont like the current approach to resting and combat 100% (i really like some things they added like the weapons specific skills and the shared initiative thing). BG3 does a lot of things outstandingly in my eye and I was open minded for ruleset changes, but at this point (after 3 EA playthroughs) i feel that the long rest spam and current action economy balance - even as it felt like something cool and modern thing at first, because yeah you can play however you want - eventually took away from the overall experience and challenge. Based on many posts and threads here and on Reddit as well around topics like healing food, jumping, disengage, OP high ground bonus, scrolls used by everyone etc... it seems im not alone. The game obviously has very positive steam review ratio because it looks and sounds gorgeous and has a very good introduction to the world and story, but one has to consider many people like myself did not leave a steam review at all yet (i gave feedback via the launcher though) because i have some gripes which i expect to alter my experience on the long run and i save my final steam review for full game.
What i want to say, its okay to alter things/add new stuff by them but its important to make them think what some of the homebrew changes can mean for a 100 hour game, designed for multiple playthroughs, because something can look/sound cool at first (hey i can do this with all my characters any time so cool!) but it can also mean that it takes away from building really cool class-specific tactics and party dynamics through that and while i agree not everything needs to be balanced, some things being really OP can mean tactics used over and over again can make the second half of the game repetitive over time (im looking at you DOS2 with the lot of teleportation skills, the armor system and the number bloating). Keep things as they are would not necessarily be reflected in sales or reviews when its releasing as the game would be still really cool, but in the eyes of many I think these could be something holding it back to become a legendary RPG.
I do trust Larian though and I believe its a really good choice they put this game to EA first, so we can give feedback like this and they can look into making the game more cool. Im sure that they see these complains (these are popping up constantly now, its impossible not to see) and i think we will see at least some options added or more of their comments around this topic in the near future. As many others said, we also want the game to turn out to be amazing and to be enjoyed fully by as many people as possible (which includes players who would like to have more challenges and tactics in the future state of the game, as myself).