I agree, the battery life is shockingly poor. I blame touchwiz as much as anything else. I would take a slightly thicker phone for a battery that consistently lasts all day.
Samsung TouchWiz with KitKat 4.4.4 had awesome performance and battery life on my Note4, then they destroyed it with a Lollipop update (after constant update nags) and forced me to downgrade probably voiding my warranty in the process, anyone sane would have returned the phone. I don't know if Samsung or Google is to blame for the serious battery and performance regressions, but I do blame Samsung for pushing it out to its users. Many people have been burned by this and will never buy Samsung again. What were they thinking? It's not as if Lollipop offers anything much for the average user (developers are another matter). It's such a shame, as the hardware is top notch.
Well we shouldn't need huge batteries if Android was fixed. Have you seen the batteries Apple put inside iPhones? iOS is great for their hardware margins.
Note 4 is a 5.7" screen. There's plenty of room for Samsung to ship a high capacity battery. The Blu Studio Energy is only a 5" but has 5000mAh. If reviewers started giving out bad reviews to anything that can't last a 24h day, other OEMs would fall in line.
i have my s6 rooted and with a custom rom. battery is not as bad, but not amazing. if i'm on a place with good mobile signal and on wifi, i can get a day[0] of battery life with ~2h of SOT (with my pebble connected and syncing all day long).
but at the same time it's kind of worth it, because it's easily the best camera on a cellphone i've ever used.
