There can be a lot of icons above a character's head right now, and at a glance it can be hard to tell what's a debuff, what's a buff, what's purgeable and what's cleansable.
World of Warcraft had a similar problem, because it had (has?) a whole load of different types of debuff. There were poison, disease, magic and curse-type debuffs. Certain classes could remove certain categories, so paladins could remove magic and poison debuffs, while priests could remove magic and disease debuffs; if an encounter had any curses involved, though, you'd require a shaman or druid to get rid of them.
What WoW did was to give the icons for the various afflictions a thick border with a specific colour indicating the type of debuff. So say a hero was given curses called Withering Touch and Hex of Weakness, a healer could see that the debuffs had a purple icon and scream for a druid/shaman to decurse.
I think DB could implement something along the same lines to clarify matters, both in the small icons in battle, and the black box o' buffs that comes up when you hold down on a character.
Icons with a white border: these are completely unremovable status effects. For example, Hansuke's +attack buff when an ally dies, or Ferno's -attack debuff.
Icons with a red border: these are enemy buffs that can be purged (if viewing an enemy) or debuffs that can be cleansed (if on a friendly hero).
I don't know how much effort it would be, programming-wise, but it might be helpful.