Many of your organs have the potential to be useful.
In my view there should be a priority given to people who signed up before they had a personal need, but those who say that they would never give, should not be allowed to get.
Signing up should be irrevocable.
Been out of touch for a while, but this issue of organ donations got me going. From many-one, your system of priorities is the first I've seen that makes sense. Priority to people who are willing to give, and of course children.