I guess the most tricky part here is most would expect "all or nothing" regarding specifications.
I've looked into this in the past myself, and there are subsets of SVG (like the Tiny spec), which would be more feasible to support for the start, but even then there are quite a few things that would get very tricky (like intersections).
Think having a complete spec would probably against "easy" and/or "light", but at the same time it would be nice being able to load svg graphics, even if we're talking about simple shapes and outlines only.