I just went back and watched a load of Michelle Kwan clips, then some Yu-na Kim, Mao Asada, and Caroline Zhang's too. And I feel like Caroline is really not quite there yet as a performer, though I think among the US ladies only Alissa Czisny is ahead in this respect.
It's interesting that Michelle's programs when she was younger were technically much more challenging and varied than later (starting around 19 or 20), not just in terms of the 3T-3T, but also she did many more transition footwork and moves in the field and interesting choreography that wasn't part of the footwork sequence. Doubtlessly later on she took out more and more choreography (Ina Bauer, back Charlotte, turns and split jumps outside the footwork seq) to conserve her energy to concentrate on the jumps. But even those later programs were able to draw the audience in because she found a way to use arm motion, head motion, back motion, and speeding up or slowing down, while doing just the most ordinary cross overs or 3-turns, so as to tell a story in the music. So you felt like she was taking you on a musical journey with her even though technically her programs weren't that difficult until it got to the footwork section (which though fast and passionate were still relatively easy, she often did 95-100% of the turns only in one direction). It was more than that she was always committed to her choreography (which Yu-na Kim is, too), but she *shared* her skating experience with her audience so that everyone felt excited and part of it. It's like watching a movie you really believe in and you really cheer for the protagonist and want the best for him/her.

Whereas with Kim, even though she really tries hard to bring out the choreography, and they are very nicely choreographed programs, it still feels like she's skating *for* the audience, not with the audience the way Michelle Kwan did.
Now Mao doesn't give that whole-hearted commitment to her choreography at all, the same problem that Caroline also has. Both of them just skate through their competitive programs, focusing so hard on each of the key elements, they don't really try to bring a story alive, and not only do you feel like they're not sharing the experience with you, they're not even performing for you (like Yu-na does), but rather they're totally focused on themselves getting through the technical demands of the program. So even though both of them have better lines and flexibility than Yu-na, they aren't not as great of performing artists. The big advantage Mao has over Caroline, of course, is her speed and skating skills, and also those big axels and combination jumps. Hence her much higher PCS, though still lower than Yu-na's due to the performance aspect (I think). Interestingly, both Mao and Caroline are amazing exhibition skaters, they really come alive for the audience there. Mao's tango program is phenomenal, and all of Caroline's exhibitions are gems -- she has such an innate musicality that doesn't shine through at all in her competition programs, the only time I saw a strong hint of it was during a couple of moments in her 4CC LP circular footwork sequence. When she let herself go for those few seconds, suddenly she came to life, but the program ended very quickly after that. So it's not that they're not capable of performing with the audience and sharing the musical experience, but both of them could really use a mentor like Michelle Kwan to bring out the performers in them even under competitive stress. It's so frustrating to see the clear potential they have in exhibitions, and not to be able to enjoy it when they're competing. Well, these two are my favorite skills, and I really hope that they bring their A games this Olympic season.
I think Alissa Czisny should also be commended for her commitment to the choreography and performance from beginning to end, even though all the falls and mistakes trip her up and make it so easy to lose focus on the performance. She's getting rewarded with higher PCS not just for her elegant positions, which Caroline also has, nor for her speed and skating skills, which are ordinary, but for this clear commitment to choreography and her artistic skills. I'm actually really pleased to see judges give Alissa high PCS, which lately has been so single-mindedly been dominated by the speed factor. Actually Alissa and Sasha Cohen are alike in this respect, they manage(d) to showcase beautiful, artistic programs and perform with heart, even though neither is particularly impressive in speed or skating skills (the way Yu-na is).
By the way, I do think that speed and skating skills are related to performance skills, because having greater ability to speed up and slow down at will, and a wider range and dynamics of physical motion, give the skater a larger vocabulary with which to build a performance. But the two are not the same. Yu-na uses her speed and skating skills to great artistic effect, Mao uses her even greater speed and skating skills to much less.