Love cruising, have been going since our DD's were the same age as yours and they're now 16 & 18.
I love that we can all do our own thing during the day, but meet up regularly, certainly at mealtimes.
I think the cruise line you choose has a big impact - we go with Disney and have never shared dining tables etc. I think also the fact that it's all inclusive except alcohol (which isn't too expensive) is great - food, ice creams, soft drinks all covered, and without people being silly on free booze.
Disney customer service is fab, and you really feel special - but it's easy it avoid being Disney-fied, the mouse isn't in your face all the time.
On port days we tend to just wander on our own, we did trips one year but wouldn't bother again unless there was something you particularly wanted to see.
Kids clubs are great and vary activities depending on the attendees. For example, my DD's both prefer arts and crafts to sport, and they've always been able to do that.
Cinemas, theatres, Pools, slides and splash zone, language lessons, cooking demos, family games, quiet areas, adult only areas including pool, shops... can't beat it for a family IMO.