No Larian thinks that High Advantage and Ground effects from D:OS was a good feature and we make it a Core Mechanic in BG3. Its standart in the Editor and this mechanic was before the first 5e rule in the game. After that decision they implemented 5e rules and "Oh no we have problems lets tinker at AC, HP and other values". The reality is that Larian D:OS Gimmicks > 5e rules and the "adapting" is another word for "mess with it". No one with brain will implement 5e rules first and implement such a homebrew rule second and make all the work useless.
And for the "realistic" fans: Dwarf and halflings have against "normal" races automatic disadvantage because heigth ;O)