The Battery:
Above all the major role is played by the battery. If you are having a big size phone and the battery drain really fast on that then no one is happy to spend such a huge amount on that. Without a good battery life every phablet is like a waste. But here in Galaxy Note 4 and Galaxy Note Edge there are expected battery upgrades. Samsung is going to push a lot more new thing here. Like fast charging and long battery output.
Samsung has promised that these new models are capable of working for longer period compare to the older series. Here the battery takes 50% less time to charge fast. That means your phone can be filled within 30 minutes. And there are few good energy saving feature in the phone that can help you to presser your battery for longer period. This is what really required in a Smartphone without which using it is not so easy.