Good list @Maximuuus. I think it combines "BG-ness" and "D&D 5e-ness," which you kind of mention.
BG-ness would be more "evoking the feeling/playstyle of BG1&2" -day/night -add dyes -better UI -worldmap -party size -party formations
5e-ness would be "is the game using the 5e rules and/or balanced based on 5e-like rules" -reactions? (idk how reaction/instant spells work in 2e) -backstab/high ground (kind of. High ground advantage/disadvantage mechanics? 5e-ness. High ground at all? Both 5e and BG-ness. But Larian is obviously not going to remove the existence of high ground) -HP bloat/AC reduction -action/bonus action + new actions
Both -cantrips shouldn't create surfaces -enemy special attack/items -less useless items and more d&d items -scroll usage -dipping -dice roll ability scores(?)
