Nordic,
You and I have a very similar situation. I have three boys, age 6,8, and 12. And I have a wife who doesn't enjoy boating. She did however instruct me to buy the C-Dory. Her exact words were, "if you buy a different boat you aren't taking my children...".
I liked the C-Dory for all of the reasons C-Brats note every day on the site, but also for the ability to lock my boys inside a closed cabin with me while at sea. I take the boys out regularly -- usually to Catalina or Santa Cruz Island -- in both cases about 25 miles over open ocean. I wouldn't feel comfortable taking them out in an open cockpit boat (or with them in the cockpit of the C-Dory) since I am often busy with 2 hands on the helm in 2-4 foot seas and would not be able to keep my hands on them. And as you know, boys will climb onto almost anything to get a better view (transom, gunwhale, chair, each other...)
The trick is to configure the interior in a manner that allows 3 boys to find solid seating when the boat is moving. I found great ideas from other Brats -- I converted the dinnette into the commuter bench (based on Little Mac's ideas pictured
here).
Once I had the commuter bench, I found that the boys slid around (and off) like we used to slide across the vinyl backseat of the old Ford station wagon in the 1960s. So I installed a hand rail for them, and built a step for them to grip with their feet -- the step doubles as a chart cabinet (I'll try to post some pictures when I get a chance). So far so good.
The kids can drive the boat, romp around the cabin, and play (the 6 year old gets a bit sleepy so I keep a spot in the V-Berth clear for him. When the trip gets long, and the swell picks up, they can sit comfortably and hold on. They LOVE the waves -- me, not so much. But I always know where the boys are, and that they are safe.
If we had the $$ I'd buy a Tomcat -- which would be an even better fit for the family. But, with a growing family (and a house in California) I'm lucky to afford the 22 -- and though tight, its an excellent fit. All things considered, I don't know a better boat for a family.