I think my ideal commentator would be a former judge or technical specialist that has a personality. Someone who could accurately call elements as they happen without thinking "What jump was that? Double or triple?" Someone who could explain underrotation or wrong edge takeoff to the average Joe or Josephine. Someone who could call a spin as it's happening-- back or forward, position names, changes of edge, etc. But even more importantly, that person needs to have an enthusiastic (not necessarily always positive) attitude. The ability to get fans excited about what they are seeing.
I feel that Jeff Buttle may become a fantastic comentator. He's started it already.
He is a skater and also trained as a judge. Unlike many of the current commentators, he experienced CoP himself. That would be a great advantage. Moreover, he was famous for being good at CoP. He was also precise in his elements and knows about PCS-aspects of skating very much. So he could tell the qualities of elements and performances.
He also seems a very smart, intelligent person. He delivers his well-thoughtout opinions in a calm, objective manners.
Personality-wise, he comes across as a very pleasant, likable personality. He would not make comments that are overly critical or mean. He also has a nice voice. He is not too chatty, either. He obviously loves the sport, too.
I was thinking of Japanese commentators as examples and thought that Midori may have one of the best personalities. She becomes emotional and excites the audience as well. But she is not very reliable for the technical assessments. She too often makes bizarre mistakes.
On the contrary, Shizuka is very reliable for the technical aspects. But she wouldn't make the audience "feel" it. Further, her explanations often go on even when the skater goes to the next moves.
Among current skaters, I would love to see Daisuke become a commentator in future. I would not think Mao would be very good at commentating. But Yuna may be pretty good. Tomas and Johnny may be interesting ones to have, too.