Re: How many #1s will we have in 2014？
Serena has big points from all the tournies spread out the whole season, so she is at an advantage to hold on the number one spot with a buffer, even when she does poorly/ not playing in a short period of time. The one player can replace Serena is Aza and not until early next summer, since Aza also has her majority of points in the st half of the season.
To sum it up, the most likely scenario in number of #1 player next year is 1 ( Serena), or 2 ( most likely Vika if Serena injured/ taking breaks). There is a slim chance that someone else outside of those 2 will take over the top rank but not without the help of them.