I would even say that without EA all 3 acts would likely have been good as Larian would not have wasted so much time rewriting the story and characters to whatever the most vocal EA players wanted. And without the rewrites and intact artistic vision BG3 would be a much better experienced than the mess we have now where so many things do not fit together because of rewrites.
Well, you can't blame ALL the rewrites on EA.
At least some of the rewrites were done because of Larian themselves (Daisy and Karlach for example)
Though, you can argue that without EA and thus the need to put together some sort of version of the game out early, they could spend a bit more time in pre-development so they could hash out things like characters and the main plot of the game BEFORE they start actually making the game and getting VA's involved (However, none of this would prevent them changing their minds mid-development anyway like with aforementioned Daisy and Karlach)
I suppose this might simply be a flaw within Larian themselves. That they're really, really, really bad at actually planning things out. They're more of a "Make it up as you go along" type, which means rewrites are common (Whether they're requested by EA players or not). Thus instead of having a good structured story and characters, it's more things are surface level great, but the depth is lacking because they're literally making stuff up as they're developing the game.