I know iPhone gets good battery life, but I want class leading if their device going to cost that much. My current phone has class leading battery life and the battery size is 2600mAH. If it had 1800 mAH, I'm sure it would get similar battery life... to an iPhone 6. I generally use benchmarks from different tech sites to to make a relative comparison and get an idea of what I SHOULD be getting. Xperia Z3 series was leading in all battery tests and lo and behold, it's had the longest battery life out of any device I've ever owned and lasts longer than all of my friends phone, whether iPhones or not.
I'm not complaining about the 16 GB out of principle. It's 2015 and I'm not even sure of the cost savings from keeping that base instead of 32 GB. When I owned the HTC One M7, 32GB was a sweet spot for me in terms of storage. I actually filled that space up with the more graphically intensive games, videos, and albums from Google Music saved to my device. iPhone can now shoot 4K video and that will fill up disk space insanely fast. General consumers use there cameras a lot and with the push of afford 4K capable devices from all the TV/Laptop manufacturers, they just might want to see their content that they've recorded.
iPhone's each year seem to gain a little more efficiency. I expect this year to be the same, even with the smaller battery. There are still devices that give similar or better battery life on the Android side. This is something that they just need to push more and expanding the screen size should help them achieve this.