I don't plan as much as I used to; I used to be quite precise as to the order I'd like to do things, and taking a break was for wimps. Now that we go more often, I'm not nearly so about things. Like most of you, I do book adrs, and what reservations I get and when may dictate the park(s) we visit that day, and I do try to avoid the MK on the weekends. And I have an idea in my head on how best to tour any given park on any given day, but it's not written in stone.
I will share this one story about "winging it." Last trip out, I was kinda hoping to get to the Studios as early as possible, with Toy Story Mania being so new. In fact, I wanted to get there at opening. My dear Slappette decided we'd be better off resting that morning. Besides, last few trips, it always seemed like the Studios was a ghost town. Not wanting to cause friction, I agreed. We arrived to the Studios about 90 minutes after opening, there was a posted 2 1/2 hour wait, and Fastpasses were for the end of the night. Wound up getting FPs for, like 8:55 at night, figuring we'd do a few things now, rest, have dinner and come back (though the original plan that night was to take it easy, too). When it came time to go back, we got on a "Studios" bus after waiting a half hour, and we were the only ones to get on the bus at that stop, it turns out the bus driver made an announcement BEFORE we got on that instead of the Studios, this bus was going to MK. And he changed the lettering on the bus AFTER we got on. So when we got to MK, needless to say, we were miffed. The only thing the driver would do was take us to TTC where we waited over a half hour, where we transferred to the Studios. Got there about a half hour before closing, and our FPs had already expired. This was one time I was grateful that they usually don't check end times on Fastpasses. We finally got on (and yeah, even by my old fart standards, it was awesome), but I did go to Guest Services to complain. I prefaced my complaint with "I know it's not your fault, but I have to vent..." the manager was sympathetic, especially since we wasted so much time waiting for a bus not going to our destination, then waiting for another bus that would. He gave us bonus FPs for everything at the Studios...that we wound up not being able to use anyway. Wound up giving them to some kids at the Saratoga Rec Center.
So...I don't see a problem with planning. Had we gone to the Studios as planned, much of that would've been avoided.