If they allowed tinkering with the Hero4, I think quite a lot. Live action VR came to life from using Hero3 & Hero4 cameras right off the shelf. There were people that figured out how to control the hsync & vsync of the Hero3 to help capture stereoscopic recordings. This solution was broken with the Hero4. However the lack of this level of sync made the GoPro footage incredibly difficult to get good stitches in VR.
When GoPro teamed up with Google to develop the Odyssey, they created a back pack to communicate with all of the attached cameras to get the desperately needed syncing between all cameras. Not only did all 16 cameras start/stop in sync, all 16 were in hsync & vsync. It's as close to a genlock as one could get with a GoPro. However, this was a closed system as the only way to get these backpacks was with an Odyssey camera system. I tried to acquire additional backpacks to add to the existing 16 to add top and bottom coverage to complete the sphere, but GoPro said no.
There are many camera people that love/hate GoPro. Loved because you can put them anywhere, and the picture quality is actually decent for what it is on the Hero4. However, they are crap to work with interface and control wise. Allowing tinkering in this world would also allow camera techs to possibly do some cool stuff that GoPro might not care to invest time. The Canon firmware hack, MagicLantern, specifically comes to mind. The exact same hardware with different programming pretty much makes it a different camera. Canon can't incorporate it, as it would cannibalize their other verticals. GoPro could have embraced/encouraged this level of tinkering as they only really have one camera type.