The only problem with staff that I see is that the bulk of our damage comes from ground targeted abilities. If someone moves, our damage is reduced by almost half (from what I've seen at least).
I was thinking about how it could be fixed and had an idea when doing the volcano fractal. The boss in there adds a burning aoe onto the player and when that player gets close to someone, they also take damage from it.
If something like this was added to our Lava Font, Ice Spike, and Eruption, our single target damage wouldn't be nearly as avoidable as it is now while keeping our aoe. Lava Font could be similar to the ability in the lava fractal, it would do damage every second for 3-5 seconds and would add burning to targets near the affected target. Ice Spike could put a ring of icicles around the target that follows it which, after a second or two, thrust inward causing raw damage to the target and explodes for less damage to all enemies near. Eruption could cover the target’s skin with stones, which explode for little damage but adds bleeds to it and everyone near
The damage may have to be lowered a little bit to make it balanced but it could be a good fix. Just an idea which will probably never happen. Oh well.