If I was in Larian's shoes, i'd do the same. Their assets/style works and look great. There's still plenty more time for BG3 to find its visual identity, either through special effects or charater models, as Im sure some of those visuals are indeed placeholders. I just saying I dont mind the similar visual style. But some people will hate no matter what.
Its funny everybody seems to have forgotten Icewind Dale...it came out after BG1. Different developper, same engine, riding off on the success of a great game. It was an EXACT visual copy of BG, no one complained at the time, why now?
Im aware you cant please everyone, but my guess is there are way more people that like the D:OS style than people that dont. And I personally believe that using it for BG3 is a good move.
Quick clarification. While Black Isle, the developer of Icewind Dale, was only a publlisher for BG2, they actively helped with development in BG1. It's not a very good comparison; Black Isle was already working with BioWare and Interplay on the other games, it wasn't a passing of the IP to someone brand new.
EDIT; clarity note; iirc Black Isle was part of Interplay, as well.