As much as I don't like apple and iOS, iOS 7 actually looks pretty decent to me, yes pretty much everything has been on android etc. for years now but at least it is better than what they have done previously, which is nothing except an extra row of icons
Of course they aren't going to just throw everything on the iphone 4 as the hardware is old now and so wouldn't be capable of running it perfectly well and of course they won't give the older iphones every new feature/change, even if they were capable of running it as they want to force current iphone 4/4s customers to upgrade to the iphone 5, every company does this unfortunately, just another form of marketing
The thing is, at least they are not leaving the phone out completely unlike every single android phone that only gets 1-2 major android updates and even then, it takes forever for them to be updated unless you have a nexus device.
What version of android is the desire, nexus one, nexus s, galaxy s 1 and about 100 other android phones stuck on??? How do those phones run these days?
As for whites and battery life, it will make zero difference if it were black, iphones have LCD based displays so white uses just as much power as what black would, if it had been AMOLED based screens then yes battery life would have been impacted.
So far they haven't been too bad regarding that last point, however, I am sure once more ads/marketing stuff comes out then they will make it out like they were the ones who came up with this stuff