To me,
Commando = extensive planning, try to see everything or as close to everything as possible, rush around
Carefree = minimal to no plan, hit our favorites, then after that, whatever we see, we see, whatever we don't fit in, who cares, stop and smell the roses
I also think of "commando" as more once in lifetime type touring. I need to fit it all in case I never come back mindset. Whereas if you have a season pass or go frequently, it is easier to adopt a "carefree" attitude because whatever you miss this trip, you can catch next trip.
We usually do Disney "Commando" style. We arrive before park opening and stay until the park closes. We plan almost down to the minute. I think our last big trip to Disney was broken out in 15 minute increments. Pretty much every detail is planned out in advance - what day we go where, what and when we ride, where and when we eat, what shows or parades we are going to watch. Literally, the whole day is mapped out step by step, planned ahead of time. It doesn't mean we never make changes to the plan, but in general, we try to follow it as close as possible.
We do this for a few reasons.
1. We normally go in a large group, about 8 people who don't split up. Trying to get 8 people, many of them kids, all on the same page is a recipe for disaster. We've learned over the years having a preset agreed upon plan works best for us. Everyone knows that their "must do" is scheduled in.
2. It stops indecision and arguments / complaining. Having a plan, we minimize wasted time with a bunch of people standing around trying to decide what to do next. You know the whole - What do you want to do? I don't care. Whatever you want to do... and then the inevitable happens, we finally pick something, only for someone to complain they don't want to do that, and half an hour later we are still standing around!
3. Minimizes wasted time, walking, backtracking, getting lost, waiting in long lines.
4. Maximizes what we can see in a day. We have a lot to fit in as everyone wants to see something different. Disney is also expensive, and for us, part of feeling like we are getting our monies worth is being able to see everything. We don't go to Disney very often either, maybe once every one to three years, so we really want to fit it all in since we may not be back for awhile.
5. We don't miss out on activities or meals that must be planned in advance. Disney has a number of attractions that you must book in advance. I always feel really bad for the kids who have their heart set on doing something and can't because Mom and Dad had no idea you needed to book or sign up in advance. If you've ever taken time to read any of the complaints on BBB about Disney or Uni, you'll see so many with people complaining about something that could easily have been avoided with some planning. "My kid had their heart set on meeting character X, being a Jedi, eating with, doing the dessert fireworks, they were too short," type complaints.
6. It helps with budgeting. I usually know almost down to the penny what our meals will cost because I have every restaurant whether it is quick service or an ADR planned out.
7. This one is probably us only. But, the kids actually like having a schedule. Especially, for the one high strung child with anxiety issues. The schedule is like her safety blanket or something. It helps her relax because she knows what we are doing when and that her favorites aren't going to get missed.
8. It helps with my sanity because I don't have to answer, what are doing next, a hundred times, and the kids are also better behaved when we have a schedule as well.
Now, Universal, we usually do Carefree.
We sleep in some days, make park opening other days. Have no real plan. We decide what we are doing next as we go. It is very laid back and relaxing.
It's a different dynamic for us there, so it works. We don't stay together, so it is easy for everyone to just do what they want, when they want. We almost always have EP, so we don't have to worry about waiting in lines. We have APs also, so no worries about not getting our monies worth or not fitting everything in as we usually stay about a week at a time and go about 3 times a year.
I have done Universal "commando" style a couple of times, but that has been when I was with someone who wanted to see both parks in one day, or when it has been busy, and we didn't have EP. Even then, I'd say it was a toned down "commando" from Disney as Universal doesn't really require meal reservations and has very few things you need to book or plan for in advance.
The only issue we've found with our "carefree" touring at Uni is that there have been times we have missed out on shows we wanted to see or thought we'd have time to do something later in the week, and then never got a chance. Not a big deal for us since we go so often, but if it was a one time only trip, I might be a bit disappointed. So, you do have to be ok with missing out if you adopt a completely care free aditutde to touring. I think most people probably fall somewhere in between.