Just a a reminder, however with the release of Legion, Blizzard will be releasing the inactive character names since apparently they don't release them on request anymore.
Here's the confirmation - Requesting a Name Be Released for Reuse - Blizzard Support
This happened in WoD too from what I remember, so if you have a couple of minutes to spare around release time (most likely after release), you should start making a list of names you'd be interested in and test them out.

Good luck! 

...