I have really apprehensive and mixed feelings about this... on the one hand part of me feels that it's about time, and maybe the right time to bring Xamarin's tooling into the fold... their cross platform tooling for VS has been great, and .Net via mono has seen some integration of MS's new .Net core codebase where appropriate.
The paranoid in me acknowledges that outside of MS Office, they've pretty much never kept a non-windows client project alive for more than two major releases. I wouldn't mind seeing the VS Code codebase become closer to what VS proper could have been, and seeing more cross platform support in that regard. I do like what they've been working on in Azure services and integration, just hoping the teams don't come in just to die in a year or two (Managed JScript, IronRuby, IronPython for starters).
I'm honestly hoping for the best, but that hope is definitely tempered.
1) All of .NET is open sourced under the Apache License (not some weird MS license)
2) Xamarin had started taking thousands of lines of code from the open sourced .NET framework and replacing parts of Mono with it (like System.Decimal, etc). So that merge had started happening anyway.
3) The "Mono" differentiation was probably going to go away with .NET Core maturing.
4) MS needs a quick step up with cross platform toolkits for .NET, and nobody better than Xamarin, who's been doing it for a decade.
If they abandon Xamarin, you still have an APL'd .NET framework that's fully developed out in the open, and nobody is really left in a lurch. You can fork it.
The paranoid in me acknowledges that outside of MS Office, they've pretty much never kept a non-windows client project alive for more than two major releases. I wouldn't mind seeing the VS Code codebase become closer to what VS proper could have been, and seeing more cross platform support in that regard. I do like what they've been working on in Azure services and integration, just hoping the teams don't come in just to die in a year or two (Managed JScript, IronRuby, IronPython for starters).
I'm honestly hoping for the best, but that hope is definitely tempered.