Daniel Dennett [Den03] writes about The evolution of freedom. I agree with him that free will is a result of evolution. It may be based on a more basic ability to predict something about what future will result from the occurrence of certain events including actions. He compares determinism and inevitability, and makes definitions so that in a deterministic world, not all events that occur are inevitable. He considers that freedom evolves in such a way as to make more and more events evitable, especially events that are bad for the organism.
Dennett's ideas and those of this paper are in the same direction and somewhat overlap. I think SDFW is simpler, catches the intuitive concepts of freedom and free will better, and are of more potential utility in AI.
Consider a species of animal with eyes but without a blink reflex. Every so often the animal will be hit in the eye and suffer an injured cornea. Now suppose the species evolves a blink reflex. Getting hit in the eye is now often evitable in Dennett's sense. However, it is not an exercise of free will in my sense.2 On the other hand, deciding whether or not to go through some bushes where there was a danger of getting hit in the eye on the basis of weighing the advantages against the dangers would be an exercise of free will in my sense. It would also be an evitability in Dennett's sense.
Evitability assumes that there is a normal course of events some of
which may be avoided, e.g. that getting hit in they eye is normal and
is avoided by the blink reflex. My notion of free will does not
involve this, because the choice between actions 
and 
is
symmetric. It is interesting to ask when there are normal events that
can sometimes be avoided.
The converse of an evitability is an opportunity. Both depend on a distinction between an action and non-action. In the case of non-action, nature takes its course.