I saw someone on Icecrown Wotlk a while ago with a working Defile cooldown Weakaura. It's not the standard one, basicallly what it does is make a circle reticle countdown anticlockwise 5 seconds before Defile came off CD, or is about to get used. Right around the time it says "Defile soon" in DBM, when everyone usually spreads out. There's no cast bar for the ability until The Lich King uses it shortly after.

I was wondering if anyone had the import? The "other addons" trigger for DBM doesn't seem to work and I tried every chat option I could in "Other Events". I'm using version 4.0.0 on if that makes a difference :)