I know right... I'm also a .NET developer and I wonder in particular how this new move will relate to .NET Framework.
I understand that .NET Core is sort of a subset of it, a new "fresh start" with refactoring done as well as platform-specific code cut in order to be able to support multiple platforms. And that .NET Standard covers .NET Core and .NET Framework as an umbrella.
However, where is Microsoft's focus now? Is .NET Core the future? What about .NET Framework 5? Will it happen? What about UWP? .NET Framework include a _ton_ of legacy stuff now. Windows Forms. Heck even WPF can be argued to be in the past, now that UWP is the future? UWP isn't directly interchangeable with WPF even though the technologies are confusingly similar. What about ASP .NET vs ASP .NET Core? What about Entity Framework vs Entity Framework Core? Is Microsoft honestly going to move them ALL forward at a good pace? That sounds like an insane undertaking!
I'm sure they want Windows devs to develop UWP apps for the Windows Store. Still, are they cannibalizing on that platform with this move? Windows Phone essentially doesn't exist. Xbox? Many wouldn't care about universal Windows apps and suffering by having to follow "weakest link support" due to non-existing smartphone platforms. Many devs would hit a MUCH larger target if developing .NET Core and targeting the web for anything UI related.
I wish Microsoft was more clear on this, but maybe the issue here is that they don't know either where they're going since it depends on where the devs are going... This whole .NET ecosystem is becoming extremely large and complex, even when singling out Windows. A whole lot has happened in a short time that it's dazzling.