This changes the setting quite a bit - yes, changes it a fun way - you can be anything at all but "anything goes" changes the feel of the setting. Now the cities of the Forgotten Realms feel more like Sigil than BG2 era Baldur's Gate.
This is just how I feel about it. You can't have Sigil without establishing all the rules and tropes it subverts first. The commitment to authenticity, and use of fantasy's long canon is sorely lacking from all the world-building I see from the powers that be.
And all of this before Larian gets its hands on the lore - lore that the Larian ceo doesn't appear to know or to value. (although I think he, unlike WotC understands that people like alignment)
With that in mind though, I think that Larian can't really be authentic to the setting, because they're receiving a compromised work of art. Continuity has been rebooted twice, and currently doesn't really want make up its mind over what is still canon, with everything being made less precise (haphazardly, re:Errata!) to cater to the 'anything goes' mentality that should be implicit within the medium. For that reason, I think if I had been in Swen's position I wouldn't feel terribly bothered to conform to the setting either, in fact, I'd probably feel like another Baldur's Gate game would be a good opportunity to revise and correct a lot of the errors and mistakes of what I'd been given. Adaptations between mediums offer a great opportunity to clean up such messes.
