Mind Probe has been used quite often in my games lately, and I'm beginning to think it might be problem. The psyker using it is a Rank 4 Astropath Transcendent will WP 56 and Psy Rating 4. He uses the power at Fettered, so Psy Rating 2 and takes the -20 penalty to make the probing subtle giving him a Focus Power score of 46, resisted by the target's WP. He has Mind's Eye which extends the range to 20 metres. Full use of the power require 5 rounds = 25 seconds. So, if he's within 20 metres for 25 seconds he has a fair chance of reading someone's entire mind like a book without them ever noticing.
My concern is that this one power can really disrupt many storylines and there's not really any reasonable way to prevent him from using it on almost everyone he comes into contact with. I know that I can make some targets harder with either psykers of their own or untouchables, but both of those are fairly rare within the setting. The player is also fairly careful and smart and uses Psynisciece to check for such things regularly.
I think the Mind Probe power is fine so long as it's doing the forcible mind **** approach, but the subtle ability to plunder thoughts at will (until Fatigue eventually saps him and makes him spend a few minutes in quiet Meditation) seems really disruptive to many storylines.
Anyone else have similar experiences with this power? Any good solutions that don't unnecessarily gimp the Astropath?