Our trip overlaps yours and man did I wrestle with this. I started out with a balls-to-the-wall, morning-to-night, tour-de-force of MK and AK.
Then people told me I was crazy and I should build in a break. So I redid everything with mid-day breaks.
Then I got a mean case of FOMO and cut the break in half to add a few more attractions.
Then I realized that over half of the break would be spent in transit from the middle of the park out to the front, getting transport back to the hotel, and then coming back. So I put the breaks back in.
As it stands now we’re doing a long (3.25 hour or so) break on the MK day, and a slightly shorter break while at AK. Even with the limited operating hours, and even with only 2 days total in the parks. The things that ultimately led to this decision were:
Lots and lots of advice on here and elsewhere saying it’s a good idea
Both my son and I have limited patience for crowds and long waits. Some unstructured time in the middle of the day where we can recharge isn’t “missing out on more stuff”, it’s "investing in being able to fully enjoy the rest of the day"
We want quality of experience over quantity. I’d rather plan fewer things and have the mental energy to enjoy them than drag an exhausted family onto 7DMT at 830pm because galdammit we’ve gotta see everything.
The general pattern I fell into was to RD both parks, have a tightly planned morning, take the break, and leave the afternoons more open for day-of FPs, spontaneous decisions, etc.
If you think your family can power through then more power to you