I loathe cases (even the thinnest shell), and am not sure if this counts as "naked", but I've had very good results with a full-coverage screen protector.
All my devices (every iPhone iteration since original) have been naked save for whatever screen protector I put on them and I have only once broken a screen when it was dropped (actually, while I was changing out the screen protector).
The aluminum backs of the 6 are so tough (and the S even more so with the new alloy supposedly) that I can't really see much except cosmetic damage occurring from scuffs in most falls, and a screen protector that *goes to the edges* goes a much longer way than I thought in screen damage/shatter protection from a lot of falls.
I've only ever put the device in a case when it's going near/on/in water, to Burning Man, or climbing (when, really, it normally doesn't ever come out of pack/pocket, really, and if it does, it's tethered to a gear loop/rack loop). The bottom line comes down to: don't drop it, and if you can limit your drop potential to 3-4 ft (table/pocket height), I think a solid screen protector will go a very long way to making naked work because the backs are solid enough and the frames durable enough that naked is viable for the most part.
For wet, highly alkaline dust, or "high potential energy with rapid conversion to kinetic

" environments, well, naked is just asking for trouble, though.
I have already had my 6s plus slip out of my hands 4 times. I am
By no means a clumsy person. I am terrified of handling this phone without a case !
How do you "naked" iPhone user cope with the unavoidable slippage of the hand ?