While I think the iPhone 5 screen size is starting to feel a tad small, a little increase like the Moto X screensize or the Xperia Z1S would be nice. Not not really enjoying the Nexus 5 size because even doing something like pulling down the notification drawer from the top of the screen is super awkward with one hand.
The other thing I'm not feeling is that Android doesn't quite seem as responsive as iOS (or Win 8 on my Surface Pro). This was something I noticed in the Nexus 7 while I had it and I still kind of feel it in the Nexus 5. I don't know if it's because the Nexus 5 still has
the response lag issues of other Android phones or because of different animation cues or what, but there's just something missing for me... I don't quite know what it is but I just feel like I am not getting the same kind of feedback that I want to get. This is most obvious to me in the keyboard - the keyboard is nice and large and easy to type on but for some reason it just feels... I dunno. Less immediate.