I'm still really impressed by the incredibly good battery life the iPhone 6 has. It give me a constant 6-8 hours of usage time everyday, and by that I mean real usage. I use my devices. Quite heavy usage too.
So I definitely do not need a bigger battery. In the very rare cases where I can't charge the iPhone once a day (I actually don't know how that would be possible to not be able to do, but anyways), I just take one of the many portable battery power banks I have with me in my bag. So no problem at all really.
So once again I will say that Apple did the right thing making the iPhone 6 as thin and light as possible. Much better for the user experience.
Check some of my latest battery life screenshots below (they are in Swedish but I think you understand where to look anyways):