2. The Point about Chinese Writing and Video are mostly true. As a Phone, and purely as a phone it is rather hard to argue about the quality iPhone offers. Indeed Single Handed operation is important if not the most important factor. However these days they aren't using it as a phone anymore. Phone has neglect into a relatively 2nd class function. The region ( I mention the region as CJK, and some other countries close by; ) uses Whatsapp, ( or other type of IM that most of US and EU users never heard of ) more to communicate then calling. While it is extremely popular to use iMessage in US and EU. This isn't the case there. Writing, ( Specific to Chinese, since Japaness and Korean has a comparatively simpler and default input method ) is harder on a iPhone with a smaller screen. Since IM is used more often then Calls this create another barrier for users compared to a larger screen, and much better selection of input method on Android devices.
The Video Part as well. Compared to US and EU users. CJK regions are very used to Subtitle. ( Yes even the video is in their own languages. And of coz all the Hollowood movies will have subtitle as well ) Now imagining watching Video on iPhone compared to a Wider devices with Subtitle. The Subitle would have taken significant amount of space.
3. It is hard to explain the Korea Pop to everyone. KARA, Super Junior or Girls Generation. If you dont know them dont worry. You properly know Psy from Gangnam Style. The pop culture, mixing in the 10 times more advertising budget from Samsung compared to Apple. It is not hard to understand why these are more popular region where K-POPs are hot.
But knowing Apple. Chances of Releasing a bigger iPhone is slim or next to zero. I was hoping they release a 3.8" and 4.34" with iPhone 5. But Since they took the 4" size that is likely to be the case in the foreseeable future. And even if they did release a bigger screen size version. It properly wont be called an iPhone then.