The new best friend is a telepath and I still reserve a chance to hope she's actually brainwashing Uiharu to be her ally. She's only level 2 but considering they spend a lot of time together, she has had all the time to do it ever so slowly. Actually that would be the best tactics anyway rather than an even more sudden change everybody would have noticed for sure. She just hides her villainous true personality behind the victimized and sad mask of a really good actor.

It doesn't seem to me Uiharu much cares about her own power. Like you said, it has tremendous possibilities in fact but when have we seen her train at all? All she cares about is doing rather unchallenging work at Judgement, and that's it. She doesn't have any ambitions whatsoever and without ambitions it's pretty hard to actively strenghten your personal reality.

Waking up the comatose children would be actually quite easy, and Mikoto even knows it. All she would need to do is to get Touma, make him lay his hand on the head of one of them and then that person could be waken up medically or otherwise and there would be no chance of going berkerk with the esper powers. Of course if waking up is not the actual problem but staying sane while awake, then that would solve nothing. But they seemed to me making a big deal about the moment of waking up specifically.