I am usually using Mana Radix Aura and Enhancing Aura (+4 % base damage to DDs) with my group consisting of druid, mage, chanter and SK. I started to wonder if using the old Twincast Aura (+9 % twincast chance on any damage spell) instead of the Enhancing Aura wouldn't more effective for aDPS. Any thoughts ?
It would be more effective. If there were nothing else going on besides the plain % number, 9 > 4 = more than twice as effective. There is more going on besides the plain % number, so it's much more effective even than that.
While you can't just compare the two values (Twincast 9% is a chance for something to happen, while Enhancing 4% is always applied to the spell base damage), I believe you are right. Let's see (calculation with the Rk II. values for the spells (10% and 5%): If we have a 30k DD that is cast 10 times this will result in 315k damage with Enhancing Aura (ignoring criticals and other stuff) With Twincast there should be statistically 1 twincast triggered, resulting in 330k damage. Adding to that Twincast works on all damage spells (including dots with intially DD component) and Lifetaps while Enhancing only works on DDs using Twincast should be better most of the times. I think I just answered my own question. The only situation I can think of where Enhancing Aura would be more effective would be during a burn when the casters punch their Improved Twincast AA.
You got it right. I only use enhancing for short duration burns (Shei mission). You can start a longer fight with enhancing then swap to twincast when your ITC wears off, but if your timing is off it can easily mess up your burn so for longer fights I only use twincast.
You say this, but the arithmetic that you followed with clearly demonstrates why one very much can just compare the two values
You can also pretty easily group the Field of Scale - Final Confrontation raid nowadays, too, to get Rk. III Twincast Aura unlocked, which is 11%.