As a healer, most of the time I’m targeting the tank and when I have the spare cycles I am casting my dots and debuffs “through” him using a macro so I don’t swap targets. This though makes it impossible to show when a debuff/dot has worn off so I can recast it. I would like to suggest that any active spells you have cast show up in something like the persistent buff window so they can be tracked even when you don’t have the mob targeted.