I agree that the split is about right. I did 4 on Oahu and 5 on Maui (with 3 on the Big Island squeezed in between). We covered just about everything we wanted to see on Oahu. I'm glad I went - I had to get to Pearl Harbor one day and Haunama Bay was extremely cool - but I probably won't go back. I'll be spending all my time on Maui, and maybe sampling Kauai.

I do agree that you need to get away from Waikiki. The Dole plantation, the North Shore, Hanauma Bay, Waimea Valley Audubon Center, Puuualakaa Overlook, hike up Diamond Head, Nuaanu Valley Rain Forest, Nuuanu Pali Lookout - there's plenty to do.