For me in order to upgrade to a possible P4 I would want to have some or all of the following:
.Longer battery life, at least a full 30 minutes with 30% battery left
.When recording in 4K (for those with 4K option) to be able to record the video in 1 single file not split by the 4gb limit which is currently in the phantom itself
.Different colors
.Some type of obstacle avoidance tech
.And last but not least, something in the 20+ megapixel range for stills, because 12 megapixels in 2016 and with a 4K capable camera, really?, cameras with 12 megapixels were available since 2008 if I remember correctly, we are talking at least 8 years ago, we need more megapixels for stills