Queendork - I know nothing about Jack O'Brien, but I kind of like his interpretation. I saw the 3 plays and I would tend to agree with his assessment. The critics in England did seem to prefer the first play. I preferred the second, but I am probably biased. The role that Jack is playing (Herzen) is only introduced at the very end of the first play, and then he is featured predominantly in the next 2 plays. At least this is the way it was presented in England, and I don't know how much Stoppard has changed it. I found Stephen Dillane to be totally riveting in the role of Herzen, so I found the second play to be the most memorable. He was wonderful in the third play too, but at the end of a trilogy day, you're just trying to stay awake.
The first play sort of is Bukanin's (spelling?), now played by Ethan Hawke, so it will probably be very popular.
I found the third play to be the weakest. I read that they are shortening the total length of the 3 plays. I did not have a problem with the overall length (9.5 hours or so), but I thought that the third play spent too much time on a couple of characters that I didn't care about. I would have liked to have seen Stoppard jettison some of the characters in the third play, and explore some of the others. But, he never asked my opinion, LOL.
I do not understand why this new production is offering so few trilogy days. :-/