Suggested modifications: Awareness - Experienced - Hardened. This will increase the stun resistance (more important than root resistance, as stun leaves the player helpless), reduces the cooldown allowing to have Combat Trance up more often, and finally increases the resistance to the secondary damage effects, very important in Ice and Blood.
This CA has a long cooldown and the Dragon Mage doesn't have any other temporary buffs that might be paired with Combat Trance, so this Combat Art is probably best left out of a Combo, unless placed in one by itself to take advantage of the decreased regen time granted by Combat Discipline.
Pros and Cons
Regeneration reduction allows spamming CAs in rapid succession.