Re: Too big
This is part of the reason why I long ago switched to combat/work trousers - all those extra pockets come in useful ;)
(Not that keeping my old Samsung S7 in a thigh pocket helped to protect it from damage!)
I'm currently using a 6" V30, and it's just on the edge of being usable via one-handed thumb-swipes, unless you're willing to precariously balance it on your extended pinkie. Which increases the risk of accidentally dropping it, and isn't particularly comfortable.
(And at 6'1, I'm a reasonably tall person with reasonably large hands. I've no idea how more vertically-challenged people are able to effectively use these ever-larger handsets!)
On the other hand, my personal usage of more traditional computing devices has drastically dropped since I got this handset - it's big and powerful enough to handle pretty much all social and "passive" activities (e.g. reading email, checking my bank balance).
So yeah, I'm actually happier with 6" than I was with 5.1" (f'nar). But I'm not particularly convinced that there's any major benefits from going any larger!