Mark Gurman, writing for 9to5mac, seems to have some information that iOS 9 is going to be more of a "no new features" release akin to OS X Snow Leopard. From the article:
One wonders if this step is a reaction to some of the backlash they have been receiving from many iOS users including some Apple community heavyweights like Marco Arment and John Gruber on their respective blogs and podcasts. For a little while now it seems like Apple's software has just been less stable, and less consistent in quality than it had been previously. Nothing showstopping of course, but more like a set of death by 1,000 papercuts-type issues.
Apple used to pride itself on best-in-class software design in the same way that they pride themselves today on best-in-class hardware design. While I'm sure they still feel that they do pride themselves on that best-in-class software, it's obvious to almost anyone these days that while they have maintained and improved that hardware design, the software hasn't gotten quite as much attention.
iOS 7 was a great visual refresh of an OS that was starting to feel visually stale, and iOS 8 was a great refinement of that look. That being said, there have been some things that just don't quite work as expected. There have been things like iCloud syncing issues, AirDrop and AirPlay consistency, iMessage consistency, small crashing bugs, and small notification center bugs. For example, I should never want to AirDrop a link to my MacBook Air and worry whether or not it will show up in my AirDrop list on my phone (it usually doesn't). It's Nothing serious, but it is just enough to make the iPhone feel less "effortless" than it used to.
So when I heard that iOS 9 was going to take the time to make the OS feel more consistent, and to squash some of those longstanding bugs, I couldn't have been happier. This is something that is sorely needed. In fact I wouldn't mind seeing a more "tick/tock" approach to iOS development. One year gets a huge feature release, the next year is less features, more reliability.
Actually, the way OS X is going, I wouldn't mind seeing it there as well! Perhaps for OS X 10.11 we could get something called "Yosemite Valley" which could be a release designed just to fix a lot of the longstanding issues with OS X as well. Considering that a lot of the bugs in both OS X and iOS have to do with services that both OS's share at this point (iMessage, AirDrop, AirPlay, Notification Center, etc) it may not be a bad idea to really spend a good year on both OS projects trying to really get them stable and consistent all the way through.