I have no idea why this feature needed to be a priority, but apparently rolling your stats didn't make the cut.

I guess this means you can make Minsc an actual barbarian which would be more lore-accurate to his character than the ranger class he got saddled with since the OG saga, but otherwise this seems like a pointless immersion breaking option. It was one thing in DOS2 where they wrote some leeway into the characters so you could justify them being whatever class you wanted, but the classes for the companions in BG III seem very tied to their characters. It's an odd choice, to say the least.

I wonder how this will effect quests and dialogues and so on where class tags are used.

Just odd. So very odd for Larian to go this route.