I find it really disturbing that I'm being asked to pay nearly double for the flight for the *chance* of upgrading. If I don't get upgraded I'm effectively throwing my money away.

I wouldn't be bothered at all if I could book a regular fare and then if i get upgraded pay the fare difference to an eligible fare. Or if I could be refunded the fare difference if I don't get upgraded. But paying for something which is subject to availability and then having them keep my money even if it's not available seems wrong in so many ways.