Bg3 will definitely have fewer classes and races since it uses 5e. The comparison won't make sense anyway since BG3 is made for people who have no previous experience with DND while WOTR is made for Grognards.
Actually Owlcat has a Toutorial and I think some other stuff to make WotR more new user friendly then Kingmaker was, so they are trying for both Grognards and noobs. BG3 might do that too.
