OmniSharp-Roslyn is planning on utilising VS RefactoringEssentials[1] sometime in the future[2], which used to be NR6Pack (and part of NRefactory 6). RefactoringEssentials is based on Roslyn.

So don't worry about OmniSharp too much :)

[1] https://github.com/icsharpcode/RefactoringEssentials

[2] https://github.com/OmniSharp/omnisharp-roslyn/pull/247#issue...