Okay, I think this is probably more a GM or (this is how he gets away) thing, but the fluff makes mention that he can somehow hide/shroud his psychic signature so that folks can't find him - then he escapes. I stumbled over that bit while skimming his dataslate.
I don't think it's necessary for in-game use as such but I could be wrong?
Like Eternal Warrior I think that's more suitable in a campaign setting. Always escapes, can't be captured etc.
As for Plasma weapons, I agree that they are poor when compared to Bolt and Melta weapons. Even in the bad old days of overpowered god-like inquisitors they weren't popular, they're even less so considering the general lack of heavily armoured characters at Conclave events (I don't think I've ever seen a Tyrus conversion at a Conclave event).
I've been thinking about this for a bit as I was considering sculpting a Plasmagun for the Missionary I'm working on, here are some of my thoughts:
Melta weapons are a bit too accurate when compared to Plasma, especially at the short ranges most inquisitor action takes place at. Lower The accuracy penalties to -5% on Plasma weapons, increase the penalties for Melta weapons (they are supposed to be more reliable but less accurate).
I quite like the recharge idea as it makes the weapon feel and play differently, the RIA version just feels like a riskier pistol with ammo and reloads etc.
You could go with 4 settings:
Low Power: 2D10+5 (2D10 pistol), no risk, no recharge.
Low Power multi shot: add semi 2/3, risky, no recharge.
High Power: 3D10+5 (3D10 pistol), risky, recharge 1
High power multi shot: add semi 2/3, higher risk, recharge 2
Another option would be to make it riskier the more times you fire it without letting it cool down/recharge. So you can fire it once with no penalty, fire it a second time (in a consecutive action) with a low risk + chance it'll need to recharge, three times - higher risk of overheating running out of charge and so on. Each action spent not firing it would allow it to cool down/build up charge again. Can also spend a maintenance action (checking gauges, coolant levels etc.) to double the recharge for that action (once per turn).