I don't think having all potential companions early is necessary in BG3. It was sort of an issue for me in BG2, but only because new members didn't inherit the protagonist's XP amount. If I was going to take Imoen, it would be best to go for her pretty early, otherwise if I would clear everything I could, by the point of rescuing her, she would have way less XP than the rest of the party. Same in PoE 1 - the first (and I believe, the only) rogue is found way too late, and you can't build much of a relationship with her in what little time remains.
Thankfully, this isn't a problem here, because:
1. New party members copy your XP, +/- small delta from inspiration points;
2. We can build them the way we like starting from level 1. For me, this is a huge improvement (esp. compared with NWN 2, for example. Good luck getting Zhjaeve or Ammon early).
