0.5

Coordinate changes
Cumulative versions of bar and line charts
New shape: Poincaré arc
New chart: Circos
Optimize Graph chart
Improve layout of trees and Sankey diagrams

0.6

Allow relative coordinates in low-level API
Improve testing and documentation
Fancier animations in demo application

0.7

More complex layouts:

Voronoi cells
circle packing
...

Possibly do this in a separate layout library, since no SVG is involved