If I understood correctly, you scenarios is that you are working on certain documents and decide to share a couple of them with some people. The best way to do "batch" sharing is to do it through a workspace.
So if your have doc1, doc2 and doc3 on WorkspaceA and you decide to share only doc1 and doc2 with me, you can't 'check' those 2 documents and share them. You would have to share all of workspaceA with me.
That being said, we are looking into improving the sharing experience in future releases, so this feedback is very important for us.
Thanks and I hope this helps!