This was inspired by a similar post in the iPad forums. In that thread I said that thinness/lightness is important in an iPad because it hasn't reached the ideal, which in my opinion is the same lightness as a magazine. As for the iPhone, I think the thinness is seriously detrimental to the user experience. If the iPhone was one millimetre thicker you'd probably have an extra 25% battery life and virtually no difference in heft or hand feel. To be honest, the iPhone 5/5s is too light in my opinion anyway, so a little extra weight/thickness would be welcome. Rumours about the new 4.7" iPhone 6 seem to follow this disappointing trend - you would think a bigger phone would allow them to have a significantly larger battery, but it's supposedly only 1810mAh - compare that with the 2200mAh battery of the similarly-sized 4.7" Moto X and I think we're in for some pretty pitiful battery life if the rumours are true. This is especially worrying because a 17.5% larger screen than the existing 5/5s is only coming with a 16% increase in battery capacity (from 1560mAh). Probably all that extra capacity will go to driving the bigger display, a beefier CPU, etc. which means at best we can hope for the same (disappointing) battery life as the 5/5s, or more likely, battery life will actually be worse. This also leads me to believe that the iPhone 6 will be even thinner than the iPhone 5/5s. Thinness doesn't just have battery implications. A thicker iPhone would also give Apple some room on the Z-Axis for better camera optics - more megapixels, or the same number of megapixels but bigger (for better low-light performance), or Optical Image Stabilization, etc. They could take what is already easily one of the best smartphone cameras on the market and vastly increase their lead over their competitors. If the iPhone 6 is even thinner than its predecessor, we can expect little to no improvement in the camera, simply due to the laws of physics. Do you think that thinness should be a priority in an iPhone above all else? Would you accept or prefer a slightly thicker phone if it provided more/better features?