Do you think technical issue is simpler to solve than a design flaw or something?
The Ai getting quicker and more reactive as it gets polished and optimized over time is basically a given.
I think there is many reasons why we shouldn't want to have 2 more party members, especially in the current state of the game.
Just because you think you have a reason, doesn't make it a good one.
It's not like you roll your entire party with same initiative all the time.
Which is PRECISELY why it wouldn't make the combat slower. You'd have MORE chances to inject your actions in queue rather than being a spectator. Not to mention more targets would (possibly) mean less focus fire on a single poor bastard spending most of his fights face-on-the-ground.
If Larian decides down the line that they might find a workaround and have it work well - so be it - but if they continuously say that there is technical and balancing limitations to it, and 4 is what they are going for, why beg them for more to risk the games overall perception to people?
Because Larian took several bad decisions over time that made their games almost objectively worse, and I want to advocate for a better game, not for a worse one?
I won't waste two hours listing all the countless reasons a six men party makes for a more compelling experience in a single player, party-based campaign that is supposed to go on for dozens of hours and absolutely BEGS for party variety.
We already did it for weeks in other threads that everyone can read.