Personally, I'd like to add more indicators for Healing related tasks. AoE circles for AoE heals while casting. Green bars on HP for Healing Over Time effects that haven't fully ticked yet. Things that make random co-healers able to coordinate better, basically.

The other thing would be a compromise on parsers. Scores after instances basically. These would indicate one's raid DPS performance (a numerical rank relative to others in the instance and a letter rank for SE's expected DPS performance for the class would be fine), Overhealing percentage, damage mitigated. Number of times they prevented lethal damage, number of raises, deaths, and so on.