I disagree that it's just being pedantic. Calling it BG3 does imply some expectations of gameplay. If final fantasy tactics was called final fantasy 8 it would have left a lot of people disappointed and frankly mislead. If a studio made Half life 3, but it played like call of duty or borderlands (even set in half life universe), it would not be what people wants or expects, even if the game in isolation is fine.
I can understand core gameplay changes being upsetting, but decades between releases and adapting to a different engine/developer/ruleset can do that.
It's like Fallout 2 to Fallout 3. The change was jarring, the lore messed up, and Fallout fans were peeved. When Fallout New Vegas adapted the same gameplay changes, but with appropriate lore from the original developers it was acceptable and considered the spiritual "Fallout 3" (rather than Van Buren).
Same with GTA changing from an isometric game in GTA2 to what it's become now.
