'm not sure I'd have needed a whole lot of depth to make this work. For me it's more of a nuts and bolts mechanical thing. The reason I like thinking about it this way, the party comps w/o repetition, is because that gives us some hard numbers to work with.
For example, say each party comp shown in the first image above had an associated ending or finale sequence. During the final ascent, the party chosen would result in a full on conversation similar to the one that we got when the Tadpole was first consumed. Except instead of each party member just spouting off their generic lines, expressing their misgivings about the tadpole or their desire to make use of it pragmatically, we might have commentary from the crew regarding the final battle and everything that's happened to bring us to that point (the big stuff). We get that set piece pump up rally at the end, but that's all focused on our Allies, and not so much the active party. I'm talking about stuff specifically for the chosen active party.
If it's 120 potential combinations for the party of 4 (player +3), then each one of those comps could have had a unique ending/finale run with it's own final banter-thon. Even with doubling or tripling to account for the various ascended vs love interest vs good vs extra evil permutations for each companion character, that's still way more manageable than like 17,000 endings or whatever they teased to that one journalist who spilled the beans. 120 seems manageable, or at least it's a place to start. 210 would be better in my view. More party comps means more replay to my way of thinking.
The issue I see is that, in the course of the campaign, the player probably runs multiple party comps at once, perhaps seeing each of the comps listed at least once per campaign, since the active party is completely overshadowed by the camp collective. We can switch out party members with ease, and the game encourages this with the personal quest switcheroo.
The only point where that dynamic changes at all is during the final ascent, where we lose access to the camp and have to choose which 3 people are going to join us while facing the Brain. If there are 120 combos for that, each one should feel very different right? But I don't know that they do really. Like it barely matters who we brought along for that, since we'll get similar post game recaps at the camp celebration regardless. Everyone who didn't die still gets to make an appearance and say their piece. The companions we bring along interact with us (Tav/Durge) but not really with each other. So bringing Shadowheart or Lae'zel or Astarion, we'll get whatever story stuff they have to offer individually, but we don't get a special option where bringing those 3 together as the final crew gives us something unique. Compared to say Shadowheart, Lae'zel, and Karlach with a different scene, cause now Shadowheart and Lae'zel are reacting to having Karlach as third puzzle piece in that comp, instead of Astarion. It would have been simpler to achieve with things like running commentary from banters rather than full on cutscene sequences probably.
Is there a real point to trying to completing the game again with each possible party comp in BG3? Not really, because they all overlap already. If you've played the game with Lae'zel and ascended Lae'zel, you've basically seen all the Lae'zel stuff already. It's not going to make a meaningful change, just cause Shadowheart is also part of the final party comp too. I'm not really sure how they planned all this out, doubtless the flowcharts are massive and the ven diagrams pretty ridiculous, but I think they lost focus on what would probably have been a simpler approach had they simply started with the party comps as the floor or foundation to build from.
