Coming from Android, I also found the lack of back button incredibly annoying at first also, but now 8 months into the iOS experiment I've just gotten so used to going through the anywhere from 2-8 steps necessary to mimic the back button to go back to where I was, depending on the app, that it's just second nature now and I don't really think about it any more. It's ridiculous really, but true.
However, I'm starting to care less about not having the back button now that "swipe to go back" is being implemented all over the place. In fact apps that haven't implemented it yet are starting to piss me off and I find myself looking for alternatives.
Hopefully iOS8 will just make swipe to go back universal and then it won't matter any more.
I don't understand how going back one screen takes 2-8 steps? There is either a button at the top left of the screen which won't say 'back' but it will take you back one screen, or you can swipe the screen to the right, or in Safari there will be a left arrow at the bottom of the screen (sure it takes one press to make this visible and another to implement it). In short, there is ALWAYS a way of going back one screen, and often more than one way. You're just used to the Android system and to be honest, if I went to Android I would REALLY miss the swipe feature.