It's a guessing game for you maybe that have problems, but not for everybody and certainly not for me that even with a new Axon 7 I'm having great battery life, the same I've been having for the past 3 or 4 phones in a row and for the past couple of years with Samsung phones. My Axon, today, in a normal working day with tons of emails, sms, a couple of videos, 45 minutes of calls and some browsing here and in other forums, I've had 4 hours of SOT with 47% battery left, almost 8 hours of SOT on average just a little more than what I'm getting with my S7 edge, about an hour more than what I had with the Note 5 and I'm sure I can get roughly about 7- 7.5 with a Note 7 should I decide to get it.
The key is to know that Android is different than iOS, if you have the mentality of not wanting to remove bloat, disable unused services and apps and having the brightness at full throttle all the time then sorry, you'll be running back to iOS soon.
You should compare apples to apples, not a 1080p or 720p smaller screens on iPhones, not running the tons of services that Android runs in the background by default with the feature rich and QuadHD 5.7" screen with up to 1040 nits of brightness on the Note 7, you want better battery life, you must avoid rogue apps, remove bloatware, disable running unused services and adjust your brightness and you'll see the difference while you enjoy the best Samsung phone ever and one of the best if not the best all around smartphone you can buy today.