Resilience, a stat introduced in the Burning Crusade, has quickly become very important in the new Arena-centric PvP world. In a nutshell, it reduces your chance to be crit, as well as the damage taken from any crits that do get through. And since PvP is all about burst damage, it makes sense that attacking crits would help. It helps against melee damage, ranged physical damage, magic nukes, anything that can crit. However, one very important class of damage is incapable of critting: DoTs.
A DoT can't crit, and therefore it doesn't care about resilience. So what, you ask? Well, this means that as PvP gear improves, and gains more resilience, it protects more against all kinds of damage except DoTs. Which means that, relative to other types of damage, DoTs get buffed as PvP gear improves. Dahis of Shadow Gaming calls this "classist item scaling," and presents as plausible solutions "Either nerf DoT base damage and allow crits, or rework resilience with some flat damage reduction component, or just add some aspect that pertains directly to DoTs." And it looks like Blizzard is listening to the growing concern; in a discussion on resilience, Drysc said "We're looking into it."
So what do you think? Does the DoTs/resilience situation need to be addressed in some way, or is it good as is? For more in-depth analysis, do read the article over at Shadow Gaming, which has several good points.