Cultural differences are likely a big factor. In Asia, most people use public transportation. In the U.S., not so much. In Asia, small backpacks or a man-purse. In the U.S., not so much.
The jury is still out on how big is too big to comfortably fit in the front pocket of your jeans, and as Greg Dee mentioned, it's often the weight that matters more than the size -- although above a certain screen size, it just isn't going to fit.
But I agree with Junko about battery life being the crux of the matter. Apple should make the iPhone 5 slightly bigger, not so much because it really matters whether the screen is 3.8" or 4.2", but because the larger form factor will allow them to put in a bigger battery -- and that really DOES matter.
There's also an age-related factor in screen size preference. Older people who have become slightly far-sighted are more likely to complain that it's hard to read the iPhone 4s screen, while younger people have no problem at all with that.
In China, people must still use cash all the time and highest denomination note is equivalent to US$15. So people need to carry a lot and men have long ago embraced man bags. So housing a big smartphone is no problem at all.
Yes, I remember what a badge of conspcious consumption those Moto brick phones used to be in HK. Even the lowly messenger boys were conspicuous consumers of their pagers in those days. And now its the wide-body Samsung smartphone that's taken their place.
Maybe the market will converge to a large enough screen size to be convenient but for improved individual mobility, electronics makers may start producing a separate, smaller device that ... merely functions as a phone! :)
I definitely think that Apple is missing the boat if the next iphone does not have an OLED display (regardless of it's size). And I think that perhaps it is time for Apple to make more than one model iphone (maybe based on screen size?).
One less device theory here makes sense. It's very logical.
When I was travelling in China last month, I was truly blown away when I found so many people actully using Samsung Galaxy Tab. (I mean, I haven't seen that in NYC subway system yet when I commute to Manhattan everyday from Brooklyn!)
I did, however, hear from one of the users in China -- he actually does carry two devices. Tab for web surfing and iPhone for actually talking.
In either way, we both agreed on one thing. The crux of the issue of carrying two devices is in battery. If you are engaged in too much surfing on iPhone, most likely you won't be able to make a simple phone call at the end of your work day!
I've had a Note I bought in Singapore 6 months ago, The galaxy Note is probably THE best product i've used in years and i normally have at least 2 phones on the go (I have Sony Active i call my "Dive phone") and 5 computers with no limit on budget, i want the best for what i do and the Note stands alone. In Addition to all the above, the OLED screen is staggering with it's contrast ratio, low light videos are view-able on that screen where on any of my LCDs there show black. The S-pen and it's apps i use to whip out video based instructions at a rate 10x faster than a typed document, literally. Seriously, AMAZING product. But North Americans (as i am) are typically way behind Asia and Europe.
You don't have Note i suspect and you're being presumptuous. I've had one for 6 months, wear jeans, i'm 6ft, 180lbs, fits in my pocket noooo problem. Why, it's WEIGHT that you feel, and it's light as hell, people are blown away then they hold. You should actually use gear before you comment maybe.