The Guild Wars team has updated their Wiki page with this info on Skill Balancing.
Rather than introducing another skill update this week, we're finishing a new system to balance key skills separately for PvP and PvE. Within the next few weeks, we'll introduce PvP versions for a handful of skills. These skills will work the same way as normal skills, but have different number values (damage, healing, cost, recharge, and so on). We will do this as sparingly as possible and start with very few skills. So that we don't confuse players, we intend to keep as many skills unchanged as we can.
PvP versions are designed to target only specific skills. With such a system we can revert high-impact nerfs, such as Light of Deliverance and Defensive Anthem, to make them strong again in PvE. When we see something becoming severely imbalanced in PvP, we'd like to avoid harsh PvE nerfs without creating different versions of a large number of skills.
Skills that differ in PvP will have (PvP) at the end of their names when in PvP outposts and matches. These skills will automatically be adjusted within PvP outposts and matches. All players have to do is equip the skill as normal, and it will use the PvP version where appropriate.