It's just YOU prefer 4.3" screen. Not everyone, not women and my grandparents. There is always an optimal size that the manufacturer decides when making phones. If you go by the logic bigger is better, then 5" screens are better than 4" and 6" inch would be better than 5". It's insane and doesn't apply to mobile universe.
Do you think, Apple can't make a 4" screen earlier itself. Do you know how hard it is to pack 326ppi with 640x960 retina display and fit it on a 3.5" screen when compared to making lack luster displays with 4" screens and call it "SUPER AMOLED" (Read Galaxy Nexus S, the flagship phone introduced when iPhone 4 was released). Galaxy Nexus S had 233 ppi, 4" and a 480x800 resolution. Don't tell me you all went WOW for that and bought it for big screen. Then, what happened? Does the phone have ICS update? The same phone beat iPhone 4 in specs wise in your opinion right? Does Samsung care about it's users and provide an update? NO. While iPhone 3GS owners still enjoy iOS 5.x updates. Beat that.