The test of a theory is its ability to cope with all the relevant phenomena, not its a priori 'reasonableness'. The latter would have proved a poor guide in the development of science, which often makes progress by its encounter with the totally unexpected and initially extremely puzzling.
Science cannot tell theology how to construct a doctrine of creation, but you can't construct a doctrine of creation without taking account of the age of the universe and the evolutionary character of cosmic history.
Well, it's because I gladly acknowledge some ideas that are part of process theology, but which I think are not tied to all the details of process thought, and are very illuminating and helpful.