What I feel that it’s lacking- a sense of chaos and unpredictability. Psykers- and ESPECIALLY untrained, unsanctioned psykers?- are notorious for wild and sporadic outbursts of warp energy and mad rambling, etc, but our psykers all sorta act like highly trained savant experts?
I understand it’s really to balance something like that, but could there be a frenzied, unhinged psyker variant that sorta peels back some of its inhibitions in favour of unhinged chaotic powers? Like maybe a Wild Magic take on Empowered Psionics- a chance for your Burst to become Unstable and proc an additional weird effect, like a chance for brain burst to randomly spread to nearby enemies, or for you to start projecting Smite-lightning from your eyes while you have a weapon out, or a cloud of swirling Assail needles to surround you? That sorta thing.