I think title says pretty well what I desire, but let me explain.
In DOS2 whenever a companion joined your party they sort of told you what class they were and then offered that you could pick another. That was great!
In BG3 that system wouldn't make so much sense, since the characters story and personality is closely tied to their class, Shadowheart's story just wouldn't work as anything but a Shar Cleric.
So my suggestion is that the player be allowed to choose either the default ability distribution or pick their own. I think Shadowheart's character would still work perfectly fine if I made her strength based so should could actually hit anything with melee weapons or had her start with 16 dexterity. I recently played a "multiplayer" game with 3 custom characters (Fighter, Cleric, Warlock) and Astarion and found combat a lot more enjoyable because their ability points were optimized for my playstyle. I did miss the banter and their constant complaining about my decisions though.