I think where you stay also influences this answer to this question in addition to having young kids--- at least it does for my family. When we stayed at AoA with kids that were 3 and 1, we had the park hopper for flexibility but we didn't really use it. We forced ourselves to try a second park on our last day. It was just hard for us to do that with our kids-- we just tried to get a full day out of each of the parks we were at. I really disliked packing them up and taking more than one or two bus rides a day. It just wasn't all that efficient for us and we would have gotten less done (not more) if we tried to do two parks the same day. And if they napped at the resort, it would have been really hard to get them up and out for hours at night. So we just stayed out all day at one park from RD to dinner.
However, having bought into DVC, we stay at BWV when we go now. Even thought we have three kids (including 1yo) and a fourth on the way, we hop into Epcot or DHS nearly every day for food, dessert, drinks or a late night ride or fireworks. It's just so easy. I imagine that anyone staying at a Monorail resort, BC and YC might say the same thing. It's just easy to hop around, especially if you are there more than a few days. I would probably still get hoppers if I was at a different resort, but I'm not sure how much I would use it and I would probably kick myself when the trip was over. But staying at BWV, we use the hopper all the time and don't find it inefficient at all. We can always stroll the little ones (sleeping or not), right into the parks.
