Far more clumsy and random than a blaster
My rule of thumb about psionic or similar abilities is that if that they are equivalent in power to mundane things then there should be no balance issues. For example, if a psionic attack is as powerful as a mundane weapon then the equivalent capability can be achieved with an armed NPC. If it's more like the capabilities of a 15th level wizard in D&D then you might have some problems with balance. Something like a Jedi mind trick might be replicated by a character with really good crap artistry skills but an infallible telepathic probe might be too powerful or maybe should come at a cost - perhaps the target can feel the touch of the probe, or maybe it's not always reliable.Psionics: they’re in the setting. They won’t be D&D wizard powerful, but they will be able to do some funky stuff. They will also have some inherent limitations.
1) they’re energy intensive. The caloric intake for psionic PCs will be much higher than average. Many are constantly eating.
2) the types of Psionic disciplines available: telekinetic, telepathic/empathic, transmetabolic (able to alter the way a being’s biochemistry works), transperceptive (including powers related to hyperspace navigation) . I’m open to other suggestions for expanding the categories.
3) which psionics a PC has will be limited. There won’t be mixing and matching of types, each will only be able to manifest a single kind of power. That said, some power types may exist in different forms, and may have a version in different disciplines. For example, a telepath may be able to see or hear through the sensory organs of other creatures, while a transperceptive may simply be able to look into a remote location even if nobody is in it.
If you do psionics then think about mundane countermeasures - mind shield devices (inevitably known as tinfoil hats due to their appearance), devices that detect psionic activity, maybe artificial psionic power amplification, some device that can affect neural functions of psionic characters.
Also, one could look into psionic critters. The Traveller literature has a few of these - look for Beaked Monkeys or Chirpers, for example, or some of the critters in A2: Research Station Gamma. The Telzey Amberdon stories have a few other good ideas for psionic characters (and critters), as does Bester's The Stars, My Destination and The Demolished Man, and James Blish's Jack of Eagles . There was also a British TV series called The Tomorrow People done in the 1970s that featured protagonists with psi powers.
The trope seems to have died a death somewhat in more modern sci-fi, perhaps because one could do it with minimal special effects back in the days before CGI tech became widely available so it's not needed as a plot device now. I suspect the rise of fantasy in the past 40 years or so may also have something to do with it.
Whatever happened to ESP? Psi powers—telepathy, telekinesis, precognition, and other parapsychological activity—was one of the founding tropes of science fiction, up there with rocket ships, time t…
1 - The original 1953 Quatermass TV play coined a lot of tropes about invisible powers, appealing to the humanity in a posessed man and suchlike. They were all designed as workarounds for the limited (nonexistent) TV special effects technology of the day but were profoundly influential on sci-fi for decades. Take a look, for example, at how many tropes Doctor Who lifts from Quatermass.