With the refactoring spirit of Inkscape 0.47 in mind, I'd like to work on delegating Inkscape's math needs to lib2geom. The special goal is to convert Inkscape's internal representation of paths to a lib2geom type. Further research has to be done, but at the moment I think this would mean replacing use of NArtBpath to std::vector<Geom::Path>.
Apart from this, I will be working on replacing other Inkscape math types with lib2geom types.
https://blueprints.launchpad.net/inkscape/+spec/lib2geom-integration