As Zach wrote in his column (see
http://erinhills.com/erin_hills_golf_superintendents_corner_2.aspx for the text as well as pictures) and Derek (who did a GREAT job shaping the new green and surrounds), the concerns with the original green were its severe contours and the inability to bounce a ball into the green (even to the unguarded right side).
Part of the goal is to allow the hole to play as long as it can for the 2017 U.S. Open (even though the new green actually shortens the hole some 10+ yards). While the total length of Erin Hills seems absurdly long (with the ability to stretch the course to more than 8100 yards), that distance is somewhat misleading because of (1) the length of the four three-shotters (which average (!) 624 from the black tees) and (2) the fast fine fescue fairways. There are not as many really long two-shotters as one might expect, especially after the 10th. Therefore, it is desirable to let the 3rd play reasonably at 480-520 yards for the Open.
The original 3rd green was certainly intriguing, esp. as it reflected the natural grade of the site (fairly unusual for a two-level green). It played well from shorter distances, but not at 490+ yards. While the severity of the transition between the two levels could be looked at as a penalty for a missed approach, the narrowness of the left/upper level was just not a reasonable target for more than a 7-iron.
I am quite excited about the new green. While it fits in well with the other greens, it will not remind you of another green on the course. The bunker that was some 30 yards short and right of the original green is now a central bunker that visually dominates the approach. The middle of the green is just hidden by this bunker, while much of the left side of the green is visible and some of the right. The bunker deceives, as it actually lies some ten yards shy of the green, allowing plenty of room to bounce in a long approach and to land a downwind approach. The two back corners of the green gently run away from the golfer and will provide good hole locations. The back-left hole location will just be tucked behind the new left bunker. From the fairway, it is an entirely different-looking second shot.
While part of me was sad to say goodbye to the original green, I am really excited about the new green and can't wait to play it. While this change will benefit the Open, it will also be a fun change for the daily golfer.
Conflict of interest disclosure: I am the Competitions Director at Erin Hills.