Hi Dan! Welcome to the meta I'm one of the Slant founders.
We've been meaning to build this for awhile now, but with so many things to do we basically said "we will build it when someone asks for it".
So thanks for asking for it, I'll chat with the team in the morning and make plans to build this feature out. I've seen many user generated websites die and take the data with them, as much as I hope Slant stays around for years I agree it would be nice to have a data export. We're on it.