You seem to be saying that all the components cover the presentation of a skater, and that skating skills is just one more. That's ok, if you can explain what it is in Skating Skills that is not in the other components?
Um, the skating skills? The skill with which the skater uses the blades across the ice.
That's not really "presentation" in the old sense, but rather the technical merit of the basic skating that happens in between the elements and other highlight moves. The steps and edges and stroking.
Most fans think it is only about basic school figure turns and flow over the ice. I do too, but at the Senior Level, that's not a problem for the elite skaters.
It's not just a question of "Are turns and flow on the ice a problem for this skater? Yes/No" and then everyone who gets the answer No gets the same score.
It's a question of
How much speed can the skater generate over the ice and with what kinds of techniques?
How smoothly do the blades flow across the ice?
How deep and steady are the edges?
How much control does the skater have over the rhythm of the strokes?
How fluid (or stiff) is the movement?
How much time is spent on one edge and transitioning between edges all on one foot, vs. gliding on flats or on two feet?
How much time is spent executing difficult turns vs. simple stroking, threes, and mohawks?
How much time is spent turning in the skater's nonpreferred direction (e.g., clockwise turns and forward crossovers by a counterclockwise jumper) and how often, how easily and unexpectedly can the skater change direction between clockwise and counterclockwise edges?
Those are not yes/no answers and the answers are not going to be the same for every skater who is competent enough to reach the elite levels.
If the answers are mostly OK, good enough, sometimes, occasionally, a little bit, etc., maybe the skater would deserve 5s for skating skills. If the answers are more like very good, a lot, wow, excellent, most the time, etc., that skater might deserve 9s.
There is a skating skill when music is played. Check out Ice Dance. Timing, rhythm, beat, are all apart of it. Sad that all this is covered under Interpretation along with story lines, antics, pseudo ballet, etc. and which assumes all the skaters have musicality.
No, it doesn't assume that all skaters have musicality. It's supposed to measure
how much musicality each skater shows in each performance.
On a structural level (was the jump planned to land on an accented beat? was the step sequence planned to start and end with a new phrase of music?) that would be part of the Choreography component, among other things. On the more micro level, how well the skater expresses the nuances of each phrase of music is reflected under Interpretation. The skater who is always on the beat and always finding little details in the music to express with a turn of the head or hand or a sway of the hips or lilt in the knees will deserve higher scores for Interpretation than the skater who smiles and hits a few obvious highlights.
There's definitely room for many judges to improve the way they score these components, and for many skaters to improve the way they skate so as to deserve higher scores.