The Men of the Masters just want to defend par, for fear of having their tournament thought of as the lowest-scoring major. Though I've never played the course, I am inclined to agree that some of the playing angles have been removed, but it might have been inevitable. In order to leave the playing angles, the Masters people would be automatically sacrificing shots to the entire field.
But, call me crazy, what if instead of adding trees on the sides of some holes, they put one or two in the middles of a couple fairways, to encourage risk taking. Case in point, #11. Say we get rid of all the trees they've added on the right. Then, we put a small group of tall trees in the fairway, leaving roughly one-third on the right, one sixth taken up by the trees, and the other half to the left. This way, we preserve the playing angles, and present a decision.
Would Mackenzie compromise with something like this in order to keep the intended strategy of many of the holes? As I see it, it's a better option than just pinching all the corridors.