A 4.3" qHD screen would be nice, but resolution would be 960 x 540. Impressive, a year ago... By this time next year or even as soon as CTIA we are going to be seeing S-AMOLED HD screens that have a resoulution of 1280 x 720, true HD. The problem is they can only shrink it to 5" at present. As the tech evolves, we will see better screens on smaller phones.
I don't think phone size is growing because the manufactorers think we want bigger phones. Phone size is growing because everyone is trying to keep up with Samsung screens and that is as small as they can make them for a "True Top Tier" phone with a mind bending display.