Worked on our first Support Specialist last night, a Sanctioned Psyker and I observed a few things.
First, she has almost the same skills and talent set as the Guardsmen specialists. This didn't strike me as odd working on the Guardsmen. They're Guardsmen from the same regiment, of course they have the same basic training… but for some reason, it struck me as strange that the Sanctioned Psyker, seconded to the unit from the Adeptua Astra Telepathica, has the same skills and talents. I guess, after being assigned to the unit, Sanctioned Psykers go through Basic Training just like the rest of the grunts. It feels like that should be mentioned in the background. There's a lot of emphasis in the text about how different psykers are, fear and isolated, but no mention about them going through Basic with their unit. There should be, IMO.
Second, apart from her Psy Powers, there is almost no customization possible. 300 exp turns out to a very small amount… at best it buys you a couple of skills, or a talent and a skill IF those are from the "two aptitudes" list, which means more pysker stuff. The character's skill list gives me no sense whatsoever who this person was before the Black Ships came. I don't like that. This is role playing character, not a model on the tabletop.
Third, where are the utility powers? We made a telepath who can't read minds or send thoughts. Telekines can't move objects. Pyrokines can't light fires. Precogs seems to the only discipline to get basic utility powers. Again, this is a role playing game, not the tabletop. I can see a lot of role playing scenarios where being able to send thoughts or read minds would be a hell of lot more useful to the group and interesting to the game than the "battlefield" powers. Just because we're in the Imperial Guard, we're not going to spending all our time blowing things up and killing people.
Finally, we don't like the Comrade talents for Psykers. Firstly, if I hadn't given the player extra exp from Comrade advances, she wouldn't have touched them. Secondly, the powers really seem to be misnamed. "Ultimate Sanction" is 1d5 wounds for a re-roll… how is that Ultimate Sanction? Ultimate Sanction is "I shoot you in the head and you die." This is more like "Remember Your Training." The Overseer jumps in front of the witch-freak to take her wounds… not very Overseer-like behavior… more like "Bodyguard."