To me the first three are required. The fourth is job related and fifth is situational.

(-needed, +job use, *situational)

-Provoke
-Rampart
-Low Blow
+Reprisal (for Dark Job)
*Convalescense, Awareness, Shirk, Anticipation, Ultimatum, Interject

Now lets say Warrior

-Provoke
-Low Blow
-Rampart
+Awareness (for Raw Intuition)
* Ultimatum, convalescence, Shirk, Anticipation (redundant), Reprisal

Paladin However has Shield Bash so Low blow becomes situational and can be replaced with Convalescence.

-Provoke
-Rampart
-Convalescence (does it apply to Clemency?)
+ Anticipation (extra damage reduction)
* Awareness, Ultimatum, Interject, Shirk, Reprisal, Low Blow