1. Copout. Just because OLED wasn't widely used doesn't mean that companies shouldn't invest in futuristic tech. Heck, even the PS Vita featured an OLED screen on its initial models. Samsung owns the best OLED panels now. Yes, Apple doesn't manufacture its own panels, but it is still better to offer the best products possible. Many Android users would switch over if Apple offered comparable hardware without any compromises. I would trade off an A10 processor for quick charging, wireless charging, etc.
2. Curved displays are popular in the market now. HTC is rumored to get into the mix while other Chinese OEMs are exploring different devices.
3. I am not a fan of the bulky iPhone plus models compared to the S7/S7E size. Compartmentalization is key. Apple needs to put forth more effort into this. Treading cautiously is important because iPhones and Galaxy Notes exploded in 2016. There is less evidence to show that it's a design flaw with the 7/7+. It's not like the Note 7 with Samsung admitting fault.
4. Fast charging is a must have. I think Apple will need to ditch their current iPhone chargers and come out with better and more powerful ones.
5. A return to a glass body is inevitable since it is more aesthetically pleasing and popular amongst Galaxy users.
The Note 7 exploded because Samsung rushed out a product. Not QC devices will not lead to the idea that too beefy of a battery in such small area could lead to major end user issues.