I've never healed in this game, but if it is anything like WoW healing then I know the issue.

As a healer in WoW I would often be to focused on healing mistakes by dps (standing in fire), raising the dead, and trying to avoid mechanics while not looking at the battle. Seriously as a healer you are constantly looking at peoples health bars instead of the ground under your feet and it can be hard to avoid stuff as a result. While dispelling is important, unless you have an instant kill debuff on you, dispelling your 5% reduced stats or slow effect is at the bottom of my priority list.