I did this back in 2012 after using Android and iPhone for the previous 4-5 years and despite really finding it a good experience, even then it was becoming difficult to live without maps and a camera. I've been thinking about it again, though, and the one thing I've tried to find is a decent keyboard phone for texting. I don't mind going without a browser, etc. on my phone, but I do find communication via text to be valuable and I don't want to go back to T9 or a phone keypad to try to do it.
Same story for a lot of people: Smartphones are indispensable because of like 5 utilities, that come attached to like 50 more things that clamor for your time and attention.
Super useful:
- Maps / Travel
- Messaging/Calling
- Camera / Gallery
- Search / information lookup
- Banking
- Authentication
But then there's:
- Ads everywhere
- Notifications clamoring for attention, even from the useful apps.
- 10 flavors of social media (which has to include HN, even if it's less intrusive than most).
It's like the utility and connections it gives you are bait. I seldom feel at rest, never fully trusting an app on my phone to want to give me the best experience possible.