Why doesn't Nancy have dream powers like the others? Simple- she can't. She has been taking Hypnocil, which prevents dreams, for so long and it has built up in her body to a point that she can't properly actualize a dream ability.
The souls of the people Freddy kills gives him strength, now imagine all the deaths from the previous two films and this one up to that reveal. That's about 21 people he killed on screen and counting.
The fact that he collects their souls at all adds new levels of creepiness to all the scenes where little kids appear in his victims' dreams. Were they not just dream-imagery, but the same little kids he'd murdered when he was still alive, forever bound to do his bidding and lure others to their deaths?
Which makes the little girl / skeleton's voice crying, "Put me down, you're hurting me!" seem a lot creepier, if you consider those to quite possibly be the last words she spoke as Freddy was killing her.
Poor Dr. Neil Gordon, who is probably in prison shortly after the end of the movie. After Don is killed and the body is eventually found, the police are going to start asking questions. And who was the last person seen with the victim that ended in a physical confrontation? Dr. Gordon. Not helping matters are that many patients under his care including his assistant Nancy who is also Don's daughter, died mysterious deaths.
There's a mention of a Westin Hills patient who cut off his own eyelids to stay awake. No one ever figured out how the patient managed to get his hands on a blade, to do such a thing. Given how Kristen got committed when she awoke from a Freddy-induced dream to find herself holding a razor blade, bleeding, it's possible that this unlucky boy was also mutilated by Freddy for sport, then woke up before the killer could finish him off and was wrongly blamed for inflicting his injuries on himself.
