At the moment this spell is not exactly great. look at casters, they have wail of the banshee with a short cool down and a mass radius. Ok Implosion has a mass radius aswell, but it only kills 1 mob at a time!! surly this can't be right, this limits the amount of mob you can kill in 1 go with it. Can you either change it so all mobs around you have to make a save at the same time OR lower the cooldown OR increase the time limit/make it extendable.

Doing any of these will start to bring healers a bit closer to casters instead of just/Blade Barriering allthe time

Light