http://www.mmo-champion.com/threads/198 ... Weak-Auras
That link leads to a topic started by H2P veteran Twintop ( also a hardcore shadow priest raiding with Fast Forward).
Twintop is extremely talented at creating valuable shadow priest WA's and these aren't any exception. From what I can tell so far these WA's will be very valuable in Legion and are worth getting into now. Of course they won't work on live but its worth it to familiarize yourself with them now.
Some of the WA's include but not limited to:
Insanity bar tracker
Shadow Apparition tracker (and how much insanity each apparition will generate)
Void Ray tracker
Shadow Word : Void tracker
and many others!
Read the post in its entirety and check back as I'm sure it will continue to be updated as we get closer to and throughout Legion.