If already applied:

• Set aura duration
• Add aura duration
• Subtract aura duration
• Remove aura
• Aura variable operation
• Run aura workflow

These would be very useful, essentially allowing what you would have done in three elements, in a single element.

There are already effects for those, "Apply aura" is meant to contain different ways of applying an aura, not be a one-stop shop for all of them.