AoE healing is generally uninteresting because there's no target prioritization associated with it. Exceptions are when you're required to identify a vulnerable player who could die to a follow-up attack (i.e. T9 double Raven dives).

If you're healing in a PvP game, players usually try to focus fire or burst down a single vulnerable player to eliminate them. AoE can play a part in this, but it's more as a setup such that you're left with too many low health targets for you to react in time to all of them. That's where triaging and coordinating with your co-healer comes in. This is also why PvP healing tends to be much more interesting than standard MMO PvE healing. That and the fact that everything is trying to kill you while you do this.

The problem with healing is also partially a tanking problem. There needs to be a real and ever-present risk of tank death. And when a tank dies, it has to have raidwipe potential. Without it, the only consequence of any death is just the dps loss. There are two lose conditions: Fail a mandatory mechanic check, or raid dps attrition.

The reason why this is unlikely to change is because SE feels that if players feel stressed out over performing their role as a tank or healer, then they won't want to play those roles. You can't mess things up. Eat a raw tankbuster? No worries. There's a backup who is sitting around waiting for the chance to actually tank something again. The backup's dead? No worries. The DPS can be healed through the autos while you come back. Dust yourself off, the fight continues on, and everyone gets their loot at the end for participating.