Guild Wars developers have updated the official wiki with a laundry list of skill balance changes for both PvP and PvE. Get the link and the rationale:

Skill Balance Changes - 18 June 2008

The primary goals of the balance updates made on June 12 were to round out PvE-targeted changes we made in the last update, to improve a few underpowered skills, and to address PvP play balance issues.

Some players have objected to changes in the last update to Ether Renewal and Shadow Form. We have not seen any actual negative impact from the Ether Renewal change, but we are still evaluating the high efficiency of Shadow Form farming builds. We will continue to monitor this issue and may make adjustments in the near future. Similarly, we know that the powerful Ursan Blessing is always the subject of much discussion. Some players feel it makes the game too easy while others think it is fun. We have not chosen to make any changes to Ursan Blessing at this time, but we will consider the matter as we move forward. Finally, we know there are continuing concerns about Wounding Strike from some PvP players, but we do not believe that changes to this skill are warranted at this time. We have, in this update, altered several other skills that are commonly used in conjunction with Wounding Strike in GvG. We will observe the consequences of these changes before revisiting the Wounding Strike issue.

PvE and PvP

Most of these changes improve existing skills. A few are power reductions that are not expected to be detrimental to PvE play. Three skills (Soul Bind, Rust, and Lightning Touch) are having their core function changed to make them more useful outside of niche circumstances.

For the full list of exact changes and effects, head on over to the Guild Wars site as linked above.