Hi Soren,
At this past LGM I had a chance to discuss several of the GSoC projects with helpful people, including Chris Lilley (of the SVG Working Group). I'd explained my thoughts that what we added should be focused on exposing DOM, first for the SVG itself, then additionally for the UI, since among other things that presents a potential plugin/extension author with a single unified interface/ approach to have to worry about.
Exposing things via XPath functions, and DOM events stays in that same paradigm. It also allows us to have a simple way to expose things eventually though JavaScript (but also others). Focusing on DOM, DOM Events and XPath would give a simple paradigm that is familiar to designers, especially since they are taught DOM and JavaScript DOM manipulation in college nowadays.
Anyway, once I had expressed that in my opinion that would be a good route to focus on I mentioned that you said you would be considering that among other approaches. Chris then responded basically with "Consider? Why would they do anything else?" We had a bit of a follow- up, but the general result was a consensus that building our API around DOM will give Inkscape the best long-term benefits.
I just wanted to be sure to get that mentioned before you jump full- speed into GSoC now, since it is time.
Again, good luck,
Jon.