I know these powers are all 'fresh out the oven,' so I'm sure you haven't had much feedback on them yet. Having had a bit of time with them now, here are a few things that I've found:

Disperse: Dispersing with no one in the room (not dispersing anyone) still places a re-cast timer on you.

Also, I discovered you can disperse Imperial Centurions. Although I absolutely love this, I'm not entirely sure it is by design. :/

Randomizer: Failed randomize still places the 100+ hour re-cast timer as well.

Mirror: From what I hear you guys already know this is broken. Does nothing.

Garble: Failed garble gives no failure feedback to the user-- just returns a blank line.

Hope this feedback is in some way helpful and if you have any questions, feel free to let me know.