If all auras were on a separate timer then it wouldn't be much fun. You would be able to avoid much damage and easily regen. It is a challenge to overcome the damage. If in a team you can have people use different auras and you can even link the auras. Having every aura on a separate timer takes away the challenge.
---
Meagy :)
Spirit of Atys
High Officer of Spiritus Artificis
Never argue with an idiot; they will just drag you down to their level, and beat you with experience.