I think Carnival has come a VERY long way in the past few years. I wouldn't hesitate to cruise with them again, with my kids or without.
There are "episodes" on every cruise line.
Cruising at times the kids are out of school means lots of kids on most cruise ships.
We were on Triumph X mas 99 with our boys. Think there were 800 kids below the age of 18 onboard. Did we notice them. U bet we did. However, they didn't ruin our cruise at all. I have been cruising with Carnival since Dec. 1997, and have never seen a "frat party" atmosphere on any of my cruises with them.
What I have seen is a lively, fun cruise, with food and service improving each and every trip.