If you need a GUI to guide you through each step and can't take an hour or two to learn the platform you are using every single day then you should probably just wait until VS2017 comes out.
They've got a solid idea on how to work .NET Core, the desktop .NET framework and .NET Standard as the bridge, but the tooling for .NET Core work is undergoing frequent revisions.
For creating a cross platform library that just works it's pretty painless. Have you tried java/maven? Or webpack? Or god forbid cross platform C++?
Your problem seems to be focused on the fact that command line interfaces are not discoverable. This is true of all command line interfaces. Linux/Unix has many utilities that are quite foreign at first. But once you learn the interface (and in this case it is quite simple) you can accomplish things with quite a bit of efficiency.
I don't think I'm totally alone with that sentiment either. .NET Core was a project that had pretty high expectations from the beginning, a cross-platform, sane and simpler .NET development platform (C#/F# too!).