I was a hater of the new FP system before actually using it, as we had mastered the art of the old system. Of course, a significant piece of that "art" required my sprinting across the parks to various FP machines throughout the day so that the rest of my family could leisurely walk to rides, get snacks, browse shops, etc. We have now been twice under the new system and, so far, it has actually helped us relax a lot more. We still enjoy rope-drop to try to knock out several rides early without needing FP, but there are times that we just want to sleep in and now we can, without fear that all the Soarin' FPs will be gone before we get there (if that's one we've gotten in advance). With very few exceptions (e.g., A&E, SDMT, TSMM), most rides can indeed be secured within a few days of a trip (and often same morning, although time selections might be limited, admittedly) so planning several weeks in advance is mainly for those who enjoy the planning process (and there are plenty of those folks). I'd rather spend a half hour a few weeks in advance thinking about what I might like to guarantee as a ride on a given day than running through the parks trying to get paper FPs all day with no idea as to what timeframe I might be forced to oblige (e.g., showing up at a Soarin' FP dispenser at 9:30 a.m. to find out the first available FP is at 5:00 that evening). If the response is (or was, I guess), "well you should know that you have to get there earlier if you want to guarantee a decent FP," then we're back to planning in advance one way or another. Six vs. half dozen.
As for being tied to a schedule, the FPs give an hour window for the very purpose of NOT having to be stuck to a strict schedule. As already fought out earlier in this thread, three FPs back-to-back can be spread out over as long as three hours or pushed together into as little as an hour-ish. As for feeling rushed while eating to make a FP time, knowing well in advance what time a FP might be has helped us tremendously in this area, as more than once under the prior system, we'd have an ADR pre-scheduled but a FP time was subject to whatever time the machine told us to come back, so either we're gobbling down food and not relaxing during lunch or I'm standing at the FP machine waiting for the return times to move late enough that we wouldn't feel rushed. With the new system, I can plan for both meals and rides in order to avoid that potential conflict (more often than not...I can acknowledge there are kinks in the system). There's a lot more flexibility with FP timing that many people want to admit.