The Galaxy S7 marks the return of the microSD slot and water-proofing, and while the battery is still sealed (which doesn't seem likely to change going forward), Samsung has been a lot more generous with the capacity for this generation.
Galaxy flagships have always led the way when it comes to imaging, their cameras always being among the top performers in the market. This time around, Samsung went backwards to play a different game of numbers: fewer but larger pixels, all 12 million of them capable of phase detection. Lightning-fast autofocus is the promise, and we've already seen the S7 deliver on it.
AMOLED has long since shaken off the stigma of being all punch and no precision, to actually bring the best of both worlds. The Always On displays are all the rage this season, and being able to light up individual pixels has always made this specific technology inherently suited for the job. "Why so late?" is probably the question to be answered.