We stayed offsite with my 5yr old DD, had a park hopper and never used it.
We planned on a mid day break. Once we spent the 30-45 minutes getting back to the hotel, the pool was a bigger draw than getting back in the car for another 30-45 minute trip back in
At 5yrs old, DD wanted to mostly look around, meet some princesses, and ride the carousel. The concept of why she's leave a perfectly good park, spend time waiting for a bus just to go some place else didn't make sense.. and, quite honestly.. the trip was about creating magic for HER
Next month -
We are going back and purchased park hoppers again. Why? Several reasons
1) we are staying onsite and have a car, so the time to park hop is greatly diminished
2) she is now 9 years old.. no longer believes in princesses

and understands the concept of taking time to get to something good/new/different
3) we're going in August.. There's no way I can see her (or us) wandering around the midday Florida sun without some down time.
4) since we're staying just outside epcot (the yacht club), park hoppers allows us to have adrs near our hotel, but in a park other than where we tour that day
how we plan to use it.. hit two parks the first two days (with a 4 hour break in the middle). At the end of 2 days, the kids (we'll also have her 13 year old brother.. who has never been to wdw) will have an idea of what the parks have to offer.
at that point, they can help plan, plot out our remaining 5 days. don't get me wrong.. i'll already have a tour plan, FPPs, and adrs..

but based on what they liked, didn't, we can tweak (add another round of the cool ride.. remove the 15th animatronics ride, add more fireworks, etc)
Given the age of your kids....and depending on how close your hotel is to the park, i'd recommend skipping the park hopper this time around (unless you are super close)