It is such a big change! On a personal note, I discovered the whole world of Environmental Management through F&ES when I was a senior in high school and frantically trying to discover career paths that weren't premed or engineering (I went to a high school like Stuyvesant where the parents were just as intense as the students, sigh). Stumbling across the Yale site on a blustery March afternoon and seeing the alternatives available changed the way I saw everything -- I feel like I owe the school a lot just for that.
Hooray to the new Yale School of the Environment! Best wishes to all folks who are waiting on these decisions, and I definitely hope the timeline is closer to mid-February than March.