Slate development goes back many years. Perhaps sometimes you've got to let the field lay fallow for a season, before that next big burst of inspiration.
Good to see this still ticking. Though these days I'm more interested in static typed languages, this is still very cool.
And Atomy: http://vito.github.io/atomy/
Both of these, I feel, are interesting small offshoots that explore more in a pattern-matching metaprogrammable grammar direction, although they never became large visions or systems.