Before start, I do not think that Psyker should kill everthing in one-shot, but I believe it needs some change on talents that force Psyker to use BB.
Everyone knows that BB is very useful to kill elites, and it is true while you play on malice.
However, in heresy, you cannot one-shot kill dogs, mutants, ragers, and almost every elite that has an armor.
Except ragers, you cannot even two-shot kill with BB, it needs more than three BB to kill even when your Psyker reach level 30.
But the problem that I really want to point out, is that the warp charge only charges when Psyker kill the enemy with BB, and it’s full of frustration when you trying to manage warp charge in heresy difficulty.
BB become inefficient way to kill elite while everyone else just melt elites with their boltgun.
Yes, you can get warp charge by killing enemies with soulblaze(10%) and any other sources(4%) when you pick those talents. But it’s very inconsistent and soulblaze does very tiny damage unless you stack it.
At this moment, spamming BB is not efficient to kill elites and boring to manage warp charge when you play above heresy difficulty. But you are forced to do because you need to regenerate your toughness and warp charge to survive.
Also, most of Psyker’s talents focused on BB. I think Dev had to tune some talents to encourage people to try other play style. Until then, Psyker is not the option to play with in high difficulty. Veteran with boltgun is more efficient to kill elites in range, and Zealot with two handed chainsword deals more damage in close range. Psyker is just a glass.