When I said "if they'd increased the case thickness" what I was meaning to say (and admittedly maybe I should have spelled it out explicitly) is "if they had increased the case thickness in any meaningful way". I am fully aware that the rumoured 0.2mm increase does not remove the camera "bump" and I don't consider it a meaningful increase, being as it is merely housekeeping to accommodate other design changes (rumoured to be thicker Force Touch screen and maybe some thicker case material). To also clarify the other ambiguity, when I say "increased the case thickness" I mean the overall thickness of the device with the increase going primarily to increasing the depth of the battery compartment. I don't of course mean increasing the thickness of the case material beyond what might have been done already.
But therein lies the problem. I certainly get the fact that battery life is about way more than battery size and battery life is the spec that matters. I suspect that most other people here do as well. The issue for me if Apple reduces the battery size is more about the message it is giving about its views on battery life and that they are very different to mine.
If Apple did double the efficiency of all components then it could halve the battery capacity in the 6s and still have the same battery life. My disappointment though would be that I do not aspire to a phone that has the same battery life as a current iPhone 6. To me Apple coming out with such a device (a 6s that is twice as efficient with a half-sized battery) would be a bit like a footballer that had been left with an entirely open goal to shoot at in an important match but for some annoying reason decided not to kick the ball into the net. In this hypothetical scenario Apple could have "scored the goal" in my analogy by keeping the battery size the same and reaping the rewards of the doubled efficiency to produce a device with double the battery life of the previous model.
I'm not claiming the numbers used above are realistic goals for the 6 to 6s transition, I just used "twice as efficient" and "halving battery size" because the maths is simple and clear for the purposes of illustration. My guess is that any savings and increments in the 6 to 6s transition are probably in the 5 - 10% range but the principle of using efficiency gains to increase battery life rather than cut battery size and only maintain battery life remains.
It really comes down to a question of how much battery life is enough and if Apple go the way of cutting battery size then it is sending a message, at least to me, that they consider what they have to be enough (all assuming they could have fitted a bigger battery into the available space had they wanted to) and that concerns me since I would only start feeling that the battery life issue was solved once the battery life is at least double what it is now and maybe even three times. I really do think that acceptable battery life is the one big mountain that the entire industry has yet to conquer.
