Time after time I have always enjoyed spending time at The Grand Wailea. If you have time this weekend watch the Adam Sandler movie Just Go With It. It was filmed at the Grand Wailea a long time ago.
I own a timeshare on the Big Island and I spend a lot of time visiting that island. I also love spending time on Oahu. However, if someone was giving me a free stay with the choice between Kings Land in Waikoloa or another BI Hilton, the timeshares at Hilton Hawaiian Village in Waikiki, or 7 nights at The Grand Wailea I would spend my time at The Grand Wailea. I'm actually surprised that The Grand Wailea is one of your options. But, considering the need to get travelers back to Maui may have made The Grand Wailea a timely option.
Heck, if you have the time do The Grand Wailea and then spend a few days on The Big Island and a few days on Oahu. The islands are so different and unique that experiencing the different islands this time will help you decide where to return in the future. I'm sure you will return when time permits.
I hope your decision isn't time consuming as I'm sure you will be pleased with your time at any of your choices.