Agree. Honestly if they just made psyker tankier by feats or other mechanics, and gave him an eazier time dealing with clusters of ranged units for damnation (with staffs).
The class would practically be on par with the rest of the classes.
Other than that i guess rework trauma and buff void weakspot damage for getting low charged headshots to actually kill infantry without having to mid-full charge.
maybe give purgatus a little more range to match the zealot flamer.
But yeah that pretty much summarizes psyker. Glass cannon, but moslty glass.