There huge disscusion about here if you didnt notice 
Epic most likely won’t do this but there already 3rd party projects to implment C# even with editor integration, with source code access people can implement anything for there own
Also keep in mins you will see more Mono then .NET as Mono is open (actully too open) and multi-platform (you won’t find .NET outside Microsoft products)
Also linking DLL in C++ is not that hard, it is Unreal build system makes things harder, heres tutorial: