Maybe you don't need to compare BG2 and BG3 because they are of different times? BG3 is not created just for BG2 fans.
Whether BG3 was created for fans or not, it was Larian's decision to make it part of the series. BG2 may be old, but it was highly acclaimed at the time it came out. If Larian didn't want their game to be put next to the prequels, they'd have named it something else, but in my opinion this comparison is what they are counting on.
Also, considering the hints dropping about the Dead Three I suspect storywise they will be tying it more closely to BG2 as the story progresses.
