Been on Carnival five times & here are some recommendations:
1. Add a "California Cruise" to the lineup. The Mexico Riviera is very limited and not much else to take after you've done this area many times. California lineup could include: San Diego, Long Beach, San Luis Obispo, San Francisco, etc.
2. Provide parents with beepers to keep track of kids on ship. Kids 10-17 who are allowed to roam the ship wear a "beeper/tracking device"(eg bracelet, etc). Parents can locate their kids with a gps like tracking device. Walkie talkies aren't practical as they are too easy to misplace and cumbersome to carry all the time.
3. Offer discounts to past Carnival guests. We finally booked a Royal Caribbean cruise as there was nothing offered by Carnival to keep us on their cruise lines. We were quoted the same rates as what we found on cruise web sites.