The next phone manufacturer that will be able to make a smartphone / laptop that can last more than 1 working day on a single charge will rule the world of smart phones. Old cell phones could last 2, 3 even more days on a single charge. Battery life is currently the main thing lacking.
More would certainly be nice but smaller/cuter/more powerful generally makes for a better reason to upgrade. Especially when you can just grab a battery you can throw in the bottom of your purse and use to recharge the phone a few times if you really need more juice.
A perfect example is the correlation between screen sizes and the launch of LTE. At the time if you asked anyone they wouldn't have wanted a larger phone however carriers wanted LTE phones and the market wanted phones that lasted all day. At the time thickness was a fairly standard comparison so what happened? They sold you a bigger screen so that they could fit a larger battery without producing a thicker phone.
(Though I'd guessed it had to do with promoting movie streaming.)
My OnePlus One lasts 2-3 at least. I've never let it run down, but there were a few days when I had its USB cable plugged in backwards (doh!) and was wondering why it didn't charge.