I was just thinking that maybe the unique skill of Mask of the Harbinger coul be modified to work not only with a 2handed ranged weapon but with off-hands too, so it could be useful for casters with chaos builds too.
Probably the same consideration goes for the entire harbinger set… ^^
harbinger set is very good, if built right is viable in every game situation : you can facetank the iron maiden / fabius and farm glagiator crucible with an harbinger build.
So i’d say it IS useful.
You have managed to completely miss the point of the harbinger set.
They are making new sets specific to chaos casters coming soon.