"There are different ways to tell a story and this isn't a way that you, and others, don't respond positively to. While others do. So, what you're missing is a method of storytelling that works for you (and it's an expensive way of finding that out, though the same sentiments have been expressed here, amid the praise, since the production started)."
I think you worded that very intelligently, perceptively, and sensitively, and I agree 100 percent. Only thing I would add is that, even for those who do respond very positively to this method of storytelling, I'm sure some will agree (though others will strongly disagree) that this great theatrical experience might have been even greater if it were somewhat shorter. I do think it needs to be a long play because it does benefit from an "epic" feeling, and also I think it adds to the atmosphere of the story to have so much of the action unfold slowly, plus that increases the shock power of the final few minutes. But I think all of that could have been accomplished perfectly well in three hours of running time with one intermission, and if the play had been edited to that length, maybe the people who love it as it is would still have loved it and some of those who didn't love it might have liked it better. Of course, we'll never know :-)