The biggest issue they need to crack is battery life - they have all this graphene field work and theory/prototypes yet nobody has implemented it for the public yet...
Agreed, battery life is king.
I really struggle with my 5S as there is no way I can make it through the day ever.
Rumours of it being thinner are extremely annoying, as more battery is really a great plus.
Rumours flying that the headphone jack is going away in order to make way for lightning port connected accessories instead.
If true, a very ****ish move indeed, not cool Apple.
What if it could be thin and have more battery capacity?