So during the later chapters BG3 will follow the D&D ruleset properly? Because one of the conclusions here is that the game kinda refuses to follow the rules.
BG2 differed immensely from the rules of 2.5. That's why there's literally dozens of options on the G3 mod to go back to pen and paper rules, 'true' grandmastery or whatever or to 'un-nerf tons of things BG2 had nerfed or powered up.