Hey Tyrias.
It would seem okay...the damage reduction is only about 20% DPS (Again I can post math here if it's needed), considering the AoE reduction size and the time for the skill to launch completely. However, if we're protecting a door or turret or gun(new WZ), it is way more effective to have the damage spread out over a longer period of time to give teammates that extra second or two to get to the objective while they're being called for help.
DFA, unlike forcestorm, also has a minimal range of use...so we pretty much have to back out of the area or run and turn around if we're right next to a group to begin using it.
With forcestorm...there's no minimal range and on top of that as a sorcerer I can be standing right in the middle of it while the AoE is happening.
So, I can understand where you're coming from but looking beyond DPS, it's a skill that had it's most valuable asset nerfed and that asset is the area of effect.