I've started contributing to InkScape in my own way, I have made a dent on a filter to sanitize InkScape.
My motives are purely selfish. I'm one of the authors of SVG, I work with SVG, and I find InkScape to be an excellent tool, but I spend a lot of time editing InkScape output with vi to clean it up for use in dynamic web apps (mostly). A task with very low entertainment value. Writing filters is more fun.
islint is pretty useful to me as is now, it has a way to go before it will serve as a general filter for InkScape.