Im hoping that with the Scuttleboss removed but the Riders staying that at least some part of the Spiderfang will remain and be updated.
I could see a new Scuttleboss coming and new Spider Riders as well, keep the Arachnarok but add in the Spider Incarnate under a different name, maybe an ancient Arachnarok or a named one like Old One Eye the Tyranid Carnifex.