No. Ragzlin... can I call you Ragzlin? Thanks. It's much shorter and easier to type.
Ragzlin, I'm basing it purely on what BG3 was supposed to be based on. It was meant to be based on D&D 5e. If you take the way the game is CURRENTLY designed, it really fits more for a party of 5-6 characters. It has nothing to do with what I'm wanting or presuming.
A party of 5-6 Level 1 characters could defeat 3 Imps at a time. A party of 1-2 could not. Period. That's the logistics of it. If Larian used proper Imp stats instead of their nerfed down homebrew stats, there is very little possibility that a party of 1-2 (MC + Lae'zel) could beat 3 Imps. Period.
And IF you only had a party of 1-2, then by the end of the very first encounter, even IF you managed to somehow beat 3 imps, you would gain, using XP Split, enough experience to level up to Level 2. So it is clear that:
A. They are not using proper D&D stats but have nerfed the enemies considerably because they know you will likely (in single player mode) only have 1-2 characters on average to face 3 imps, and
B. That if you only face said 3 imps you'd gain enough XP to gain a level up after your first encounter. So they severely nerfed how many XP's you should get from that encounter so you don't level up right away.
So, what I'm trying to say is that the encounters are already based on the expectation that you will start with a party of 4 (single or multiplayer) and you'll add at least Lae'zel (and possibly Us) to your party to make a party of 5 or 6 by the time you face your first Imp encounter. Again, however, that would only be IF they used actual D&D 5e stats. My point is that the way the encounters were initially constructed, it had to be assumed you'd have 5 or 6 in your party in order to defeat 3 Imps. Then they realized that "Oh dang! There might only be 1-2 characters in single player mode. We'd best nerf everything because most people are going to be playing this with only 1-2 characters in the party by this point."
So, what I'm saying is, make it so players start with 4 Customized Characters whether single or multiplayer, increase party size to 6, and use proper D&D stats, and the entire game would be perfect for a legit D&D 5e experience with proper XP gain per encounter and proper challenge ratings and so forth.
Then use Difficulty settings to allow players to adjust to their own desired number of characters. If you want 4, adjust Difficulty to make encounters easier (nerfed) like it is now.
But for the love of all that is holy, give players the option to have up to 6 and make that the norm. Then make options to allow players to balance it more for their preference.
You always start big and then work down to small. You never start small and work big or it never works right.
If they were to balance the game right now based on 1-4 party size, they'd need to nix every encounter in the prologue and almost every encounter in the game if they were to use proper D&D stats, and that's what I'm trying to say. The game is actually, literally built for 5-6 party size. I've tested it via Tabletop. I know what I'm talking about. It is WAY to hard with a party size of 4 unless you severely nerf EVERYTHING, which is the current state of the entire game.
I've sat at more than one table where we only had 4 total players, or less, including the DM. From Pamphlets to 4e. Balance then becomes up to the DM.
1. Why are those Imps injured? Because they've been fighting on a ship that's populated with Mindflayers, and being attacked by Gith with dragons. We see evidence of this throughout the tutorial, so it is beyond contestation. So having them injured is both logical, and a choice made by the DM.
2. The intellect devourer encounters at the crash site are presumably newborns. What makes me believe that? Us. We also have evidence to suggest that they were still under direct control by the Mindflayers. What am I basing that on? Again, Us, and the scene that plays out immediately after we rescue him. So not being as powerful as they could/should be is also understandable, and then there's the incident where Sven got wiped by that encounter, so it's evidently possible that they can, in fact, win that fight.
3. At the end of the day, this game is also a SP campaign. After release, we'll be able to do something that shoots a hole the size of Texas in your idea that the game is balanced for 6 players already, Tav doesn't have to exist. Yes, we'll be able to, if we wish, pick one of the Origin characters as the main character. Make no mistake, some will choose to play as one, or all of them, across multiple playthroughs. Even if the only goal is to see more of the Origin Character stories at once.
But to get closer to where I'm at with this whole idea, the game is balanced where it is because it includes a SP campaign. Even the addition of just SH playing SP trivializes any content that comes after, in the tutorial. I'm looking at how trivial it would be with a party of 4, let alone a party of 6 or more, and thinking that it wouldn't be a great idea. In fact, I could see a 6 person party being the next barrelmancy. One mage to create surfaces, another to ignite them, or otherwise activate them, and maybe even another to CC them in the surface, so they can't get out. Along with lots of ranged DPS to take out any survivors. Yep, sounds like a really fun game to me.