For me the "BG feeling" is also being able to build a party that shares alignment, works well together and generally gets along. BG1&2 have a large selection of companions so you can always build a group you like.
Because of the origin focus, BG3 might only have 8 companions. How many are you even going to like out of them?
Yup, this is a HUGE source of my fear about the game as well. I won't ever use empty-suit mercs. I won't use evil-aligned party members, especially my first several times playing the game, with "evil-aligned" being determined by me regardless of how Larian may try to spin their characters. And I will only play with a mod that allows a party of six. So am I going to have five companions-- and fully fleshed-out companions at that--who are NOT evil-aligned in any way? I highly doubt it at this time.
