I think the retina display is one of the best screens on the market competing with samoled plus screen on Galaxy S2. most reiewers agree the deciding factor is what you use the phone for. i watch alot of video so the amoled plus could potentially be better for ME.
However i already have the retina display on my phone and at the moment i think ios5 is a bit lacklustre an upgrade so the software alone wont tempt me to upgrade. so the hardware needs to be really good for me to upgrade my handset and top of My list is a slightly larger screen. if the screen isnt larger i would be looking for a screen improvement elsewhere otherwise i will probably use my upgrade on a different handset. and anyway just because something is the best at the moment doesnt mean it cant be improved
Of course this is true...anything can be improved, but you made the comment "major improvement", which implies a serious problem with the existing hand set. There is no serious problem, bottom line, it's the best screen on the market, and when you say it's in need of major improvement, your argument about size becomes moot...i personally can't stand the huge screens available on some android based handsets, they look absurd, and the quality on the screen is simply not up to par.
We won't even get into iOS preference or opinions, since they have zilch to do with the retina display anyways. It simply comes down to personal wants, this is obvious, but when you say something needs major improvement, it makes very little sense when said "something" (See: retina display) is the best quality screen on the market.