I've been thinking about making a topic for this, but I am just going to put it here:
BG3 is not a game built on the experiences of BG1+2. It uses the setting of BG1 and the stories of BG1+2 as its setting. It uses a cinematic style and companion dialogue style from Dragon Age: Origins. It uses a combat and control scheme, and indeed borrows most of its "kinetic" gameplay from DOS2, which itself was an evolution from DOS1, which itself was a 3D reimagining of isometric gameplay from old CRPGs.
At its core, BG3 seems to be a tabletop simulator. Perhaps not with 5e rules on a 1:1 basis, but a tabletop simulator nevertheless. Outside of its turn-based combat and general exploration, the most important, attention-grabbing features of the game are centered around dialogue choices and dice rolls. Previous RPGs did not give you a visual D20 to roll every 30 minutes of gameplay, flashing modifiers to show how you might reach that minimum score. The very way the story progresses is tied to your dice rolls, and even if you fail, the story progresses in a new way. Even the narrator serves as a DM as opposed to the narrator of a story or a particular character.
What gives it away the most is the idea of the "spider web" ending that recently emerged in an article. There is one "type" of ending, but 17,000 different ways to get there. They discuss how many RPGs give you a small handful of branching paths that are set once you make a certain decision, and there's no going back. I would argue that most RPG and CRPG experiences actually "railroad" the player this way. You are given very specific quests, and at best, you can either succeed or fail. Maybe some factions have competing quests, and you have to choose one. But once you are on a path, you must stick with it, as one can see in every classic CRPG, FNV, TES, or Bioware Games. Maybe you can change the order of the quests, maybe you can choose one faction over another, maybe you can choose one alignments path over another, but ultimately there is one particular direction the game is going to go.
What Larian seems to be pursuing here is the "spider web" of the DM interacting with a specific module. The players can do many things, even derail the DM's initial plans, but eventually the DM accounts for these decisions and guides the players back to the module. They way the players get back to the main objective of the module can involve a multitude of different permutations, bounded only by imagination (the immersive sim component) and rules-contained chance (the rolling component).
What makes other games enjoyable has been the quality of the very specific stories created for the player. Here, the goal is to provide the player with respect for every way they might stray from the initial story, something only accomplished by tabletop roleplaying, or immersive sim-style RPGs.
