Hmm, that's too bad because the other islands have more character if that makes sense. An active volcano, the majesty of Waimea Canyon and Haleakala, lavender farm, seeing Na Pali via helicopter, the cat sanctuary, Kalaupapa (you can ride a mule there and back - very interesting experience), the fern grotto, scuba/snorkeling with manta rays, and so much more. So maybe you've lost interested in Aulani, but to extend this disinterest to the entire state is cheating yourself, IMO. I have noticed some folks use Aulani and Hawaii interchangeably, but it's not accurate. Or sometimes people say they don't need to leave Aulani because they've been to Hawaii when they really have only been to Oahu and therefore have never experienced what the other 5 islands have to offer - or even realize that Molokai and Lanai are options though probably not the best options for children.
Sorry to ramble, and I know this is an Aulani board. I'm just very passionate about all the things Hawaii has to offer. Since your family wants to explore more of the state, I feel the need to encourage you to give Hawaii another try.
In terms of something being the time change being worth it, I understand that's relative. I traveled a few times a year from the east coast to Hawaii until I actually moved here and it was totally worth it each time. But I went to different islands and did island specific things - many of which are named above. I actually spent very little time at the beach, but I've never been a beach person.
Re: Food. I find the Kona side of Big Island, Kauai, and Maui are much better for vegetarians and vegans because the local culture is very health conscious. I took my sister to the BI and she didn't have any problems finding vegan restaurants to eat around Kona or veggie places on Maui.