I understand what you're talking about regarding the companions, and I certainly feel the total lack of "good alignment" NPCs (I know it's early access and they have more companions planned). However, I think the EA companions fit the whole "escape from an Illithid dungeon" scenario, but that scenario seems quite ridiculous for level 1 characters.
The game has essentially recreated the exact same scenario that opened BG2, the Irenicus dungeon escape, except it's designed for level 1 characters(the opening of BG2 was designed for about level 7 to 10), but that scenario makes no sense for level 1, and the same feeling of power disconnect exists between the characters and their backstories (with the exception for Shadowheart and *possibly* Wyll- I haven't learned too much about him yet).
Lae'zel- She is a Githyanki which are generally involved in planar travel campaigns , though it's certainly possible to have a low level adventuring Githyanki character, it seems like she has experience fighting Illithid which are level 10ish(I'm not 100% clear on whether she's fought Illithid before, but the game makes it seems like she's a veteran warrior of the Githyanki military).
Astarion- generally speaking, a vampire is high level threat, even a vampire spawn should be more powerful than a level 1 character. Again, it's certainly possible for a sufficient explanation, but it's kind of defying general D&D logic to make a level 1 character a vampire or even a vampire spawn.
Gale- A level 2 wizard hardly seems powerful or noteworthy enough to be the center of a magical realm-destroying catastrophe plot. Many villages in the realms have wizards that are equally or slightly more powerful than he is, and basically every major city has a guild of wizards that are leagues above level 2.
All of these characters and their backgrounds would have made perfect sense as companions in Irenicus' dungeon when the game begins at level 7 -10, but there is a strong disconnect with their stories for first level characters. Shadowheart's story is the one that fits most cleanly with a level 1 character, though it could fit a mid level character just as well. She seems like a believable acolyte (even though she is hiding something).
BG1 and NWN2 both had openings that seemed much more appropriate for level 1 characters: Your childhood home was attacked, and you were given a concrete reason to adventure in search of answers but are just a small player in large world. BG3's is so much more in line with BG2: You're captured by a powerful evil force who is trying to take your life, but manage to escape only to find yourself in a distant part of the world you are utterly unfamiliar with and have a strict time limit to prevent total catastrophe.
