About Baldur's Gate III being Divinity: Original Sin with a Baldur's Gate theme, trolls might also be saying that, but it doesn't seem incorrect.
Equipment names? Baldur's Gate. Spells? Baldur's Gate. Races? Baldur's Gate. Combat system? Original Sin with Dungeons & Dragons elements. User interface? Original Sin. Party size? Original Sin. Party management system? Original Sin. Lack of a weather system? Original Sin. Lack of a day/night cycle? Original Sin. A lot of interactive objects? Original Sin. A lot of environmental effects? Original Sin. Story structure? Original Sin. Party member names? Original Sin. Party member personalities? Original Sin.
Some of the elements from the Original Sin games are definitely an improvement over the original Baldur's Gate games, but overall, Baldur's Gate III is far more like an improved Original Sin with elements from Dungeons & Dragons than an improved Baldur's Gate.
Combat system? DnD 5e with still adjusting the perks of the system. User interface? Originally similar to their DO titles, now distinctively BG3 Party size? DnD 5e Party management system? Greatly readjusted in the last Patch. Lack of a weather system? Would be nice, I agree. Lack of a day/night cycle? Dragon Age Origins also miss out on this one for the same reason. They would have to re-shoot all of the campsite cinematics. Also the game has a concealment system that would have to be recreated entirely with a day/night cycle. I am fine with the current set up. Day=adventuring, night= party banter. A lot of interactive objects? I would say intractability is one of the great strengths of BG3, compared to for instance Solasta where everything feels stale and static. A lot of environmental effects? Greatly readjusted in multiple Patches. Story structure? Like the three part story structure that is universal to western storytelling? Party member names? Bullshit... Party member personalities? See my previous point.
