as a pro developer with more than 50 finished games and 50+M plays of my games I can say what im missing in the C3.
- normal standalone app
- 3D (based on the modern libraries for 3d in the web)
- support for all popular monetisation tools
- prefabs
- mesh animation
- masking for sprites
- runtime preview
- support for facebook playable files.
list can be wider, but this is the main things that pro devs cant find in the engine.
3D for web is very popular now, devs who can do it, using classic JS and three JS earning the highest salaries.
many people searching for devs who can do Facebook playable ads
and all publishers asking about monetization tools in the developed games and they all has api for unity
this is why publishers asking devs to use unity
and probably construct need more than 2 devs to make the engine, to be compitative