I've been experimenting recently with retaliation for the guardian. I've come up with a build (still very much a work in progress) that allows me to spam retaliation in WvW combat. Here are the basics of what I've been playing recently:
6 V, IX (optional depending on weapon), XI
Basically, I am able to keep retaliation up nearly 100 percent of the time in combat. The key skills are: Healer's Retribution, Renewed Justice, Superior Aria, Vengeful, and Virtue of Retribution.
Just FYI, I run Soldier's Armor with Superior Runes of the Dolyak. Main weapon is a staff and secondary is a hammer or scepter/shield depending on what feels right at the moment.