Good point about the scar...though I'm not sure how he can 'lose' a power.
One thing about Peter that's interesting, and may or may not be relevant:
Peter's power is empathic. In the scene with Claude, he says that to use a power, he has to connect with that person emotionally. To concentrate on how that person makes him feel.
This might help explain why he sometimes has trouble using powers, to my mind. As well as why he didn't connect with Sylar's powers before this. Maybe Future Peter is so disconnected from Future Claire that he can no longer "interface" with her power. Of course, I'm sure there's a dozen instances where this idea is weakened or negated, but it's something I haven't seen brought up before.
As for the rest:
Evil Claire feels forced and wooden. Oh wow, she tortures people now. Still not scary. It's meant to be a shock, but it comes off as trite.
I liked the interplay between Daphne and Parkman and Molly.
I was curious about Sylar's wife, and if his son has powers. I got the impression he was trying to keep his boy well away from powers, no doubt because he didn't want to feel an urge to look at his brain.
Peter didn't try to get at Nathan's brain for his power, he wanted to "understand" Nathan. What his motivations were. What he wanted. Telepathy didn't give him the answers...Nathan's mind was too disciplined. Peter didn't trust what he saw. There was another way...an easier, surer way...and all he had to do was take a look inside...
Just thoughts.