Ivanovic and Kirilenko are mostly unable to beat the players inside the Top10 (or even in the Top20 actually) so I would be very surprised to see them integrating the Top10.
Cibulkova, Safarova, Kanepi, Goerges and Lisicki have everything it takes but injuries or inconsistency have always prevented them to reach this goal. I don't see why it should change suddenly.
Bartoli is always close but always falls short.
No one among the youngest players gives me the impression of being ready for a real breakthrough, although here we must expect some surprises.
IMO, Makarova and Barthel are making steady progresses and I'll follow them closely.
Schiavone is getting older and is probably close to her retirement. Kuznetsova and Jankovic: well, no one knows what to expect from them.
Taking into account these elements it's difficult to predict significant changes for 2013. So here are my predictions:
1- Azarenka: since her game is about controlled aggression and tactical choices it allows her to be incredibly consistent. She could very well stay at the top of the ranking.
2- Kvitova: in 2012 she was still crushing most of her opponents ranked among the Top20/30. As soon as she will recover the capacity of defeating the other Top10, she will move up the ranking.
3- Sharapova: I thought she would end about the 8th rank in 2012, but she proved me wrong. She seems to have recovered her game, so she could well stay in the Top3.
4- Serena: as good as she is, she doesn't play enough to really compete for the top spot(s). In 2012, she played what was the closest thing of a full schedule for her. She won more than 93% of her matches and was still unable to reach the number one spot. I dont think she can do better than a 3th or 4th rank.
5- Kerber: she's fairly consistent and, as a Top10 player, she'll have easier draws in 2013 than in 2012. If she keeps the same intensity, she'll remain among the best.
6- A. Radwanska.
8- Wozniacki: that's more a hope than a prediction if she doesn't improve.
10 - Zvonareva