The red aura effect that the spaulder displays looks alot like an enemy AOE. It took my wife 3 or 4 dungeon runs before she realized it wasn't some enemy attack trying to kill her and started actually standing in it. I would bet that a decent percentage of people in pug groups are confused by it as a well, causing the group to miss out on some valuable buffs. It can also be a little difficult to see the boundaries on some terrain. (Particularly areas with alot of fire/lava)
Changing it from its current red aura to either a blue flame or frost effect seems like it wouldn't be difficult, while making it less ominous looking for allies. A green/poison cloud effect probably wouldn't be difficult either, but that too would probably send unaware allies dodge rolling for their lives.
I just think some change would be good, as trying to get people to stand in a red AOE just seems a little unnatural.