Is EA a mistake? Well, recall what the game mechanics were like in the earliest versions. If Larian hadn't done EA, it would have been even less like 5e than it is now, and it would still retain the very unbalanced mix of 5e-style and DOS-style mechanics which worked against each other.
For me personally, it turns out that I could not keep replaying the same first act content over and over again. I found myself burning out, so I stopped playing EA some time ago.
Take party of 6. All Larian has to do is say yes or no. Just, "Yes. We'll provide an option for players to have up to 6 if they want.". Or "Nope. Not gonna happen. Too many issues.". Or whatever.
I was under the impression that they've already said no to a party of 6 for the primary reason that many people in the party would also force more enemies in encounters or increased toughness for enemies, which would bog combat down and make it take too long. I do watch some 5e combat livestreams on occasion and combat with lots of players does take a long time, even accounting for the manual adding of dice and the confusion.
(Personally speaking I would have liked at least 5 party members so I could fill all the main roles of melee fighter, blaster/controller, healer, and thief and still leave room for another one to spice it up, but I'm certain Larian isn't going to budge on the party size.)
