I've been on //BUILD/ and talked to the IE team with the following results:
- IE11 WebDriver is considered "done"
- There will be no more IE11 development (except security issues), so do not expect anything, especially no "really finished" WebDriver for IE11
- WebDriver for EDGE is coming, they don't know when yet, however, they want it for internal reasons as well
- WebDriver for EDGE ist definitely not finished with the official release of Windows 10.
Hope that helped a little.
Best regards,
D.R.