Datatables are not gonna make 1.0, and I think it is underestimated how much they are still in use:

Longread which gives I nice overview: https://github.com/dotnet/corefx/issues/1039

DbProviderFactory: https://github.com/dotnet/corefx/issues/4571

Schema stuff: https://github.com/dotnet/corefx/issues/3423 https://github.com/dotnet/corefx/issues/5024

I don't care that much for schema as I'm not an ORM writer, but I do have used Datables a lot as a convenient data-mangler type for importing legacy data, converting data etc. They may be "dirty", obsolete or whatever but they get the job done.