One thing that will really help with Defenders in making them a viable "Group Defender" is to Unerf the Leadership abilties. Defenders get a supposed 12.5% damage bonus for Assault. But this quantitative bonus only APPLIES to the unmodified unenhanced base damage of the spell. This bonuses does not stack with any sort of debuffs or enhancing damage bonuses.
So.. if you have a XXX spell that deals 100pts of damage (zero buffs, zero enhancers) it will now deal 112.5 points of damage. Now, as with the vast majority of people out there they will have at least one damage enhancer on a spell.
Now, this next example taken to the extreme, just for visualization with enhancers.
100 base damage spell, plus 6 SO enhancers + 200% = 300 damage. Now add on assault and that person deals 312.5 pts of damage. This equates to a 4.2% damage increase for that spell at a continuous drain of 2 End per tick. This is petty to the extreme compared to all other buffs and debuffs out there. Hell, my enervating field debuffs the critter and increases damage output by at least ~25%.
Assault does not stack with any sort of debuff or damage output
Daegon
