Blender as UE4

Could it be used, now free, Unreal engine 4 or Cryengine SDK, for creating improvements in Blender in performance, abilities etc.?
I know that’s difficult to rewite it in Python, but does someone has this direction ?

Of course, but there is a problem: Implementation, blender implementation is different to the UE one, and almost every game engine has different implementations, so you can’t simply copy-paste files to blender. ¿What can you do? See how it works, how UE does something better that the BGE, and try to transcribe it to the BGE. But that requires work and time, probably a lot. So there are few people that can do that, and fewer that will do that.

PD: Is the Cryengine source public visible?, I know the UE does, but I didn’t know that Cryengine does too.

CryEngine source code is not public, nor is the SDK free anymore.

I use blender, and while it can be a pain, (the fbx exporter sucks in blender, I’m afraid) using this plugin makes everything go super smooth. What’s cool is this lets you make your own exporters, which is pretty awesome cause that opens a lot of doors.