I totally agree that a 5" would be as perfect as could be. I have the 6+ and am right in the middle between the two models. Like many of you are saying the 6+ is wonderful to look at and use in many circumstances but is kind of a bear when on the move. I'm female and can stick it in a purse but then I may not hear or feel it. Also I'm more likely to lose my purse than my phone... I'm just used to carrying my phone in my back pocket in summer (yes back pocket!!) or jacket pocket during colder weather and then I pull it out when I'm about to sit and leave it out either in cup holder in car or else on table or desk etc. when I get somewhere (or else I keep it in pocket).
Speaking of the 6+ in cup holder in car: that works surprisingly well! I thought it wouldn't fit but it fit great and the grippiness of my clear case holds it up nicely as if purposely on display.
I haven't decided yet myself but I feel a little bit of an "ache" from gripping the big phone in my hands after a while (what a wuss) compared to smaller phones. I used the 6 today in the store with my 6+, going back and forth between the two and honestly, the 6 was too small and the 6+ too big. Ugh - hat being such an Apple fangirl!!