The gopro serves its original intended purpose. It's just people have expanded its usage .... and apparently it's CEO is now the top paid CEO in the US per cnn.com
I personally think the integration of the gopro controls into the Solo is a great evolution. However this strategy will be old news within the year. Both DJI and 3DR will have to innovate to stay relevant, else risk obsolescence.
GoPro was an idea from a guy that started selling them on a tv shopping channel, later becoming one of the most used cameras in the world. 3DR (or whoever makes a compatibility deal with GoPro) will not have to innovate cameras, because GoPro will keep making them better regardless of the drone industry. Therefore if 3DR made a deal with GoPro, 3DR can concentrate solely on the copters themselves and although 3DR may be catching up to DJI in a certain sense, being able to carry GoPros is a huge benefit.
If, according to DJI camera proponents, the fisheye is the only disadvantage and GoPro sees a profit niche in lens interchangeability, I can see this option becoming available soon, although it can be done already.