Positional tracking is what is desperately needed in the mobile VR space. This is one of the biggest differences between mobile and PC based systems. Without true positional tracking mobile experiences just don't feel good in most cases outside of video viewing and simple interaction games. I do feel a hardware solution is most likely going to be needed at this stage of the game. The processing power for most mobile phones is already coming close to its limits with just the processing of the VR experiences. With the power of a headset like the Gear VR adding positional tracking will for sure help to bridge the gap between mobile and PC based systems.