IMHO: My .NET Bets
Let us re-visit this section in one or two years (2018) ;). These are my guesses where the journey goes.
#1: .NET Native will go WebAssembly
#2: Xamarin will switch to .NET Native
Hearing between the lines from presentations, the .NET Standard Library (that is the class library evolved from the .NET Core project) is going to be used for UWP, .NET Core and Xamarin. This leaves Xamarin in the state, that they have to switch their SDKs to the .NET Standard Library leaving only the runtime from the previous Mono involvement. My bet here is that Microsoft owned Xamarin will also exchange the runtime in favor of .NET Native to reduce the overall workload for the teams.
#3: Mono is dead
After Microsoft acquired Xamarin, they “own” all three big implementations of .NET: .NET Framework, .NET Core and Mono, with .NET Core invading all classic Mono markets. For sanity they will stop financing contributions to the Mono project. Since Xamarin was the major force behind Mono, this makes Mono a dead project.
#4: A client side development model for all devices
UWP and Xamarin will compete for the users. Xamarin.Forms already supports Android, iOS and Windows. UWP only Windows. On the long run, it would make more sense to only have one, similar what Cordova can offer with HTML.
I have no idea, how that will turn out, but there is a conflict here which need to be resolved.
#5: Other languages takeover Roslyn / Omnisharp concepts
The Roslyn compiler platform and its amazing support for dozens of editors via Omnisharp without any loss of quality is a inspiration for other programming platforms, especially for the new ones like Go and Rust. Maybe it already happened, but so far it is amazing how fast the OmniSharp project reached all major editors.