Update: This post is no longer relevant as YetaWF supports ASP.NET Core 2.0 since YetaWF version 3.0.0.
Update: A few hours later, it was announced that ASP.NET Core 2.0 will support netstandard2.0. All is well. As soon as ASP.NET Core preview is updated for netstandard2.0, we will resume support for ASP.NET Core.
Unfortunately ASP.NET Core 2.0 Preview 2 is still unusable, mainly because of Visual Studio 2017 Preview 3.0 tooling issues. It takes about 10 minutes to open the YetaWF solution (see https://developercommunity.visualstudio.com/content/problem/75782/20-minutes-to-open-solution-vs-1530-preview-30-rep.html
Update 2: With the recent development, we'll most likely be able to support netcoreapp2.0 within a few months of ASP.NET Core MVC 2.0 being released, as many .NET dependencies are being addressed, both by Microsoft in their own packages and by many 3rd parties. We will continue to support ASP.NET 4 MVC 5 at the same time for the foreseeable future, as there are still numerous (non-open source) YetaWF sites with legacy dependencies.
YetaWF was working perfectly fine with ASP.NET Core MVC 2.0 (a dev version) until early May, 2017, when ASP.NET Core and MVC dropped support for net46 by moving exclusively to netcoreapp2.0. We couldn't use ASP.NET Core 1.1 because of several limitations, so we switched to 2.0 early on (when it was still called 1.2).
ASP.NET Core MVC 2.0 is no longer a viable platform for our use. Remember, YetaWF has become an open source project based on our web framework we use to host our own sites. We're Windows-centric, and our sites use numerous 3rd-party dependencies and our own, which are based on the .NET framework. And have been for years. Our sites use Windows features and can't run on what amounts to a lowest common denominator in cross-platform support (today).
Microsoft's move to netcoreapp2.0 requires a huge effort on our part to support ASP.NET Core and ASP.NET Core MVC, which simply isn't possible or worthwhile at this time. The return for investing these resources would be minimal. So at this time we're abandoning ASP.NET Core and ASP.NET Core MVC.
We will revisit this once the dust settles. Given the somewhat chaotic direction changes since 1.0, we can only hope there will be some more...