O.K. Let me say up front that I can’t stand the idea of this new FP policy.

I would like to point out some examples of how a change like this will REALLY impact our touring style. During our two trips to WDW in 2010 and 2011, we’ve used the FP system as allowed and loved it.
We only really pay attention to the beginning time of the FP window because we know we can use them anytime after that for the remainder of the day. This is all completely accepted and by the rules, as mentioned many times already. Thanks for bearing with me if you take the time to read thru the rest of this. Each of these examples are how the current FP policy has helped us enjoy or stay, and the new policy may change things for the worse. It just makes for more potential conflicts and scheduling issues. Not something I want to deal with while trying to relax on vacation.
#1 – Rope drop. TSMM and Soarin’ rope drop mad rush to the FP area. So we rush over to get FP’s. This is always a very long line in the morning. Who knows what time the FP window will be at by the time you get to one of the machines. It changes significantly just in your time to walk over to the ride and the line to get to the machine. So let’s say you finally get to the machine after waiting in line, and the window is 11:30 to 12:30. (very plausible) You have an ADR for 11:30, or the time window is during a planned show time we wanted to see? What do you do? You obviously can’t get FP’s because the time window doesn’t work. So now you’ve gotten up early and made a mad rush to get FP’s only to find out it won’t work. Do you get out of line and go all the way to the back of the line, and wait until you get back to the machine hoping for a time that will work? This can take a long time with the FP machine lines in the morning. Do you just sit and wait until the time window works for your schedule? This is a waste of time and not enjoyable!

The way things are currently, I would have gathered FP’s and just used them sometime after our ADR or show and walked away a happy guy.
#2 – Unknown FP time windows. I’m at Space Mountain late morning but want to get FP’s for BTMM to use later in the afternoon or evening. So I make the long trek over there only to find out that the time window is at 1:00-2:00. Standby is 45 minutes (very plausible). We planned to take a nap back at the resort after lunch. Well, we don’t want to wait in line for 45+ minutes for the ride (that’s why we went there in the first place, to get FP’s). So now what? Do we stand around waiting for the FP time window to get to a point that is after our planned nap? That could take a long time and is a waste of time. So we can’t get FP’s and who knows what the stand-by time will be after we get back later in the day.

The way things are now, I would get FP’s walk away a happy guy and use them later in the day.

The only park I can think that that posts the FP windows is Epcot. I know they have a large sign in front of The Land and I think on by Mission Space that shows current wait times and FP windows. That helps with this example, but is limited to Epcot and you have to be near a sign that shows the info. I choose not to use a Smartphone, so I don’t have one of the many Apps that show current SB wait times, and FP windows, so that isn’t an option. I can see a lot of walking around the parks with no idea if when you get to a FP machine, the time will work for our schedule.
#3 – Being even MORE tied to a schedule. As if ADR’s aren’t already forcing your park schedule to some extent, now the FP’s will even more. Lets say I had FP’s that had a time window starting in 5 minutes, but I suddenly saw that a show like Light Motors Action is starting soon and my family really want to go see it. The way things are now, we happily walk over to LMA and watch the show and then stroll over to the ride and use the FP’s when we feel like it. With the new policy this will not be possible.
The ability to get FP’s and use them any time later in the day has been great. Knowing you have a fun ride to look forward to if you decide to head back to the resort for a break, or park hop to another park for a while.

(we don’t park hop, but I could see this change negatively impacting park hoppers)
The enforcement of the time window will eliminate a LOT of the flexibility we’ve thoroughly enjoyed these past two years, and I’m bummed by it. I don't like the idea of being tied to a certain area of the park for a defined time window. Does it ruin a trip? No. Can it be a big hassle versus how things are now, and make vacation less enjoyable? Yes. At least it feels good venting a little.
Dan