Almost all forms of crowd control
Just like any other things, the game of Lunia is constantly changing. Blizzard will change dispel mechanics in Cataclysm, and that would be big changes. The biggest affect will be on PVP. These changes include PVP. All healing specs are going to get defensive dispels against magic, the most common debuff type in the game. Most team compositions are going to have at least one member with the capability of removing magical Lunia gold and capable of dealing with almost all forms of crowd control. That is huge.