I would be absurdly happy to find a phone like a Note 3/4 that's 2x as thick and has 2-3x as much battery. Not that the Note has poor battery life (it easily last a full 12-16 hours of pretty heavy usage).
I really don't care much about thinness in phones, but I do care about having a forever battery and I'd happily trade 3mm of pocket space for it.
If you really don't care about size there are plenty of options, especially for phones like the Note3 with replaceable backs[1].Even for the iPhone you can buy a wrap around case that embeds a battery.
I really don't care much about thinness in phones, but I do care about having a forever battery and I'd happily trade 3mm of pocket space for it.