Allow direct access to OneDrive without having to sync OR allow mapped drives.
Tony Pape commented
Can people edit if I give them direct access?
You can map your OneDrive for Business and SharePoint Online document libraries to network drives with Zee Drive http://www.thinkscape.com/Map-Network-Drives-To-Office-365-OneDrive/#ShareYourFiles, a commercial tool.
Alex Carlock commented
With client drives getting smaller (think tablets with 128 GB of total space) and OD4B getting larger (1TB-5TB) there's currently no good way to see my files. Not all applications can open files directly from OneDrive for Business, and with a small drive, I can't sync everything locally. If I could map a drive to OD4B, then I could use it as a regular drive even if the contents are online only. Another option would be to create virtual junction points in the OD4B sync folder that point directly online. Then it would appear that I'm opening/saving a file locally, but I'm really working in the online file.