So, is it dead? Rated 4 out of 5 stars

Erik is certainly an active guy as a dev. But Scriptish hasn't received any updates over 7months, and v1.8 branch haven't even started, not to mention some bugs in latest firefox versions (GM_log).

What future?

This review is for a previous version of the add-on (  This user has 2 previous reviews of this add-on.

Not quite

I believe Nils has recently corrected the GM_log issue you mentioned. There should be a new version of Scriptish out in time for the general release of FF 17.