Unofficial Patch Notes

[Wez]

http://www.dominusnihilguild.com/forums/viewtopic.php?t=10015

[Brocken]

Shield Discipline - Removed and replaced by the new talent Shield Slam.
New Talent: Shield Slam - Slam the target with your shield, causing damage and has a 50% chance to dispel 1 magic effect on the target. Also causes a moderate amount of threat. Requires the purchase of the Concussion Blow talent.
I use SD all the time. The key part to tanking in this game is that you spend more of your effort on shield management than dealing weapon damage. SD increased threat, damage, and mitigation for 20 seconds with a 45 second cool down - meaning your tanking ability vs a boss essentially doubled for little less than half the fight. Shield slam is useless by comparison - at least on paper.