Slakk,
Many of us on this board have at least one other timeshare in addition to DVC, and many of us enjoy trading through II.
However, based upon what you've written in this thread, I'm not sure you'd be any happier with conventional II trades than with II trades through DVC's World Passport Collection.
Successful trades into desirable resorts at desirable travel times require planning, patience, flexibility, and a certain amount of luck. And if you have to cancel a trade you'll face the same issues that you're facing if your cancelled trade into Ko Olina. (By the way, trading into Ko Olina is an excellent achievement for someone who is not a Marriott owner.)
As Dean has often described, there are genuine differences if you're trading directly with II as an II member (Getaways, Accommodation Certificates, trading up or down in size, FlexChange, and so one). But, fundamentally, you're still dependent upon what owners (or resort systems) deposit with II. There's serious competition from other owners at peak times, such as spring break and other weeks when children are out of school. And there may be limited timeshare availability (or no timeshare resorts at all) in places you might want to visit.
I'm sorry that you have chosen to lose your points rather than to consider the many possible options within driving distance of where you live. It appears you want an II exchange into a studio at Hilton Head -- or nothing at all. Hilton Head has great timeshare resorts, but the accommodations are typically 2-bedroom villas without lock-off capability.