I remember reading back a year or two ago (?) that they had applied for some type of permit/patent for doing this. They also applied for one to put some in the resorts for onsite guests, if I remember correctly. I guess this shouldnt come as too big of a surprise.
I see a lot of problems with this system, most of which have been mentioned: Much larger crowds in the fast pass area, longer lines for the fast passes, constantly needing to return to one location to get a new fast pass when you can only get one at a time, confusion from people when they can only get one at a time but they are all in the same location, people grabbing fast passes when they might not be needed, fast passes running out much earlier in the day, not knowing return times to make an educated decision about which fast pass to grab, and probably a few I havent thought of.
However, this is testing. All sorts of things can be tweaked. Return times could go up in post, more machines could be added to the centralized location, more centralized locations could be put in so that there are several areas that hold fast pass machines for all the rides, etc. Ill wait to hold off final judgment until I hear a bit how it works and get a chance to try it out myself.