When we were on the ship I was very happy with how well enforced the adult areas were. When they brought the kids on stage for the final graduation ceremony we were shocked to see how many kids were actually onboard. They are kept so busy I never felt overwhelmed with too many kids in one spot at any one time.
I remember having the same experience on my first disney cruise. DH and I (actually we weren't married yet, he proposed on that trip ) were alone and spent quite a bit of time in the adult only areas. On the last day we decided to go to the kids graduation...I don't know why, we thought it would be cute and we do really like kids. Anyway, we were floored when we saw all of the kids go out on the stage (and of course not every child attends this). I don't remember the exact number, but there were over 700 kids on that cruise. I never felt like kids were everywhere and I was impressed that we were able to have such a peaceful cruise with that many kids around. I agree, DCL is better at this than the other lines...even though DCL probably has more kids on many of their sailings.