The Guild Wars official wiki has been updated with developer input about the May 9th update and the fine art of skill balancing:
Rather than introducing another skill update this week, were finishing a new system to balance key skills separately for PvP and PvE. Within the next few weeks, well 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 dont 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, wed 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.
Weve decided to release our next skill balance update simultaneously with these changes. We can take full advantage of the new skill balancing mechanism and avoid multiple balances over a short time frame.