For my last trip, I planned using touring plans obsessively. I'd say it certainly saved us time. But more importantly, by obsessively planning beforehand, it set our expectations of how much we could actually do in a day.
There are two features when creating a touring plan. The first is the Optimize feature that allows you to put in all of your attractions, breaks, and meals, and out spits the absolute efficient plan. However this can cause you to crisscross the park, and if you miss a time, you will be off schedule. We did not do this.
The other feature is the Evaluate feature. This allows you to put in the attractions, breaks, and meals in the order you choose, and it will provide you the time each thing will happen. This allowed complete flexibility in the order you want to do things, and the wait times were not much more than the Optimize feature. The biggest advantage is that you control where you are at what time, if you miss a time, you are not "off schedule", and it eliminates crisscrossing. For example, I set up plans where we were in a "land" certain parts of the day. Fantasyland from 9-11, Frontierland from 11-1, etc. Then I put in the attractions, meals, and breaks, and built the day that way. With a little (or a lot in my case) of trial and error, I built plans that worked well for our touring style, that allowed a lot of flexibility, and set very reasonable expectations on what could be accomplished each day.