If iOS 9 rumors turns out to be true, I can see one last go for the A5. Apple should have dropped the original from the lineup but they didn't.
I actually hope they drop the A5 from 9. There's not much they can do performance wise for the older chip, and it gets old hearing from those 'great Apple fans' about how their old device doesn't run as well as it did on iOS 4.3. >>;