Jim:
I haven't seen Muirfield Village lately, so I can't answer that question. It wasn't nearly as wide as Augusta to start with, and the greens weren't as severe, so it isn't really a comparable situation -- but I doubt that Jack has narrowed it too much and planted trees because that's (still) not his style.
Tommy:
As for the "other" debate, well, clearly the test of "who designed something" is biased by whatever the observer thinks architecture is. Here's a snippet from Jack about Sebonack from a recent interview:
"Tom focuses a great deal on the look, and I made certain to weave in good golf shots and strategy."
The tone of which can be inferred to mean that Jack thinks he had more to do with the "strategy" and playing character of the holes (the part that Tom Paul calls "designing up the holes") than I did, even though he also admits that the routing is mine; and that he thinks that's the most important part of design. Of course, even on Jack's own designs, someone else really does the routing work and he edits and approves it, so his role at Sebonack was really not different than usual other than having to agree with me on some things.
There are others who would agree with Pat M., when he says that when the routing was done, the die was cast, because a really good routing anticipates bunker positioning and greens contouring -- I am prone to that bias myself. However, I can assure you that if I hadn't been involved after that point (or if Jack hadn't), Sebonack would be a VERY different course and likely the very features most people talk about would be different than they came out.
So, it really is a collaboration. And I'm sure Muirfield Village was in just the same way. I'm sure it pained Desmond Muirhead to talk about it because that project was considered his best work and he lost a lot of the credit for it over the years. Luckily, even if Sebonack winds up being considered the best course I've worked on, I've got some other "solo" designs to fall back on.