Guild Wars, Dervishes have always been a unique class, swinging scythes in wide arcs and using a combination of enchantments and melee strikes to take out opponents. Of course, being a unique class also leads to a lot of unique issues, which the development team is hoping to address with the coming update. The preview promises that over 90% of the Dervish skills have been changed, with the overall goal of improving the class in a broad spectrum rather than just tweaking the numbers on a handful of skills.
Among the more far-reaching changes are several Dervish skills using Adrenaline, the addition of new "flash enchantments" to allow Dervishes to enchant themselves while on the move, and a restructuring of the many "teardown" combos in place that capitalize on Dervish enchantments. Several of the new skills are previewed, as are examples of how players can use the changed mechanics to still retain the essential playstyle of a Dervish with much more flexibility than before. If you're a Dervish in Guild Wars, the changes should keep you spinning up in the best possible way.
[Thanks for the tip, Teina!]