1) The idea that reasons to benefit are person directing and so one can't have a reason to benefit a nonexistent person implies that we have no reason to revive people from the dead who no longer exist. But that's obviously false.
2) It can't make sense of the axiological non-identity problem. It seems better if a very happy person is made than if a merely pretty happy person is made. But if this is so then it can't just be grounded in people's duties--it must be grounded in axiology.
Other problems for the account:
1) The idea that reasons to benefit are person directing and so one can't have a reason to benefit a nonexistent person implies that we have no reason to revive people from the dead who no longer exist. But that's obviously false.
2) It can't make sense of the axiological non-identity problem. It seems better if a very happy person is made than if a merely pretty happy person is made. But if this is so then it can't just be grounded in people's duties--it must be grounded in axiology.