What smartphone feature do you most want so see improved in 2015?

It's a no brainer: battery life, battery life, battery life.

In all seriousness, how many cores and how much RAM do we really need? I'd happily stick with a Nexus 5 that lasted for four days over an octa-core, 64-bit monster with 4 GB of RAM and three and a half hours of screen-on time.

Well, in that case sorry @scott but I have to agree with @Kris I wan't Battery Life, Battery Life, and Battery Life

PS: It looks like there's some battery competition going on !

Better battery capacity would be nice and extended screen surface.

Battery life is important, but I think a key differentiator for many consumers is now the smartphone's camera. We have seen incremental improvements for the last 2-3 years other than the Nokia 1020; the manufacturer that makes a giant leap forward without significantly altering existing form factors will do very well.

I would like a better camera. Can't complain about battery life. The OPO is a beast.
And I would like to see more phones with front facing stereo speakers. I hate the bottom, down facing ones. Especially while watching videos

Yeah, obviously a longer battery life is something almost every smartphone user dreams about. For me this means the amount of time I can use it every day but also the amount of time until the thing dies away - approximately after 2 years. Smartphones have reached a level where it is not absolutely necessary to switch phones too often to be able to use the newest apps without lag.

I have to agree with @Kris, the battery life for the smartphones is essential, would a dream have a smartphone which can be used for a lot of time, about a week using always internet

BATTERY LIFE!!!

Gimme a 4K panel and a 10,000 mAh battery and I'm all set!

You know, for a device that we generally use to communicate with using our ears, and in view of the fact that I am part of the aging sector of the population, it amazes me that no-one talks about the ability to actually HEAR this device. Why am I not seeing reviews about the audibility of various phones. My Galaxy S4 is adequate, my husbands older phone is barely audible, not at all in a noisy environment. I don't want to have to get a hearing aid just to hear my phone. Please figure out how to increase the volume with a user-friendly section of the settings, or better yet a button on the main screen. I can up the brightness very easily in the settings, why not the volume!