Honestly, I don't think ASUS needs to offer a "solution" to the GPS issue. Merely dropping GPS from their marketing pitch and offering a refund to those folks who bought it while it was marketed as a GPS device seems entirely sufficient to me.
Bottom line is, if you want to use a tablet as a navigation or standalone GPS device, then the Prime isn't for you. Neither is the wifi iPad 2, for that matter, which of course has no GPS chip whatsoever. For everything else that requires location awareness, the Prime is fine.
I think we should keep in mind: we have a right to a product that works as advertised when we bought it. The refund (assuming it's offered everywhere) recognizes that right and offers a fair alternative. We don't, however, have a right to a product that works the way we want it to. Don't like the Prime's GPS performance, don't buy it. It's really that simple.