Apple has been doing a very good job in terms of streamlining its product. Keeping only 1 model of iPhone for each stage. iPhone 5s/ 5c breaks that. However, they are at least having very similar electronics and therefore, they can still maintain bargaining power with high volume. The rumor has said there will be 2 models of iPhone 6, large and regular size. Presumbly, they are still having very similar electronics if not the same. This will continue streamline the production and customer support. If Apple decides to keep iPhone 5s/ 5c, there will certainly be challenges ahead.
I am sure there are many opinions on the subject but for me the only reason to own an iPhone is if you aagree with Jobs' idiosyncratic vision or don't care enough to do better. I want my 3 button mouse despite Jobs' insistence that I am not smart enough to know what I need. And I want my onscreen keyboard to show when caps lock is on. And I want a better spell checker and word predictor than Apple had been able / willingto come up with. I want my phone to behave one way in the office and another way at home without me having to lift a finger. Yes, I am in the minority. Most people are satisfied with a big green and red buttons and nothing G else.