Yeah, I just copied the code from the 5 branch into this one, as Fillers used to drop blocks before the Builder rewrite. I'm not sure how I would separate Builder and Filler block breaking, because I'd love for the Filler to continue dropping blocks, whether or not the Builder does.

And I'm pretty sure the entire reason the separate drop lifespans were added is to remove the cheaper quarry option, it'll chop dirt and logs just fine, but point it at stone and they'll only exist for a moment. That was fixed back in the 1.4.7 days when the Mindcrack FTB players were exploiting the heck out of the filler.

All in all I think it's fine to drop blocks on both the builder and the filler, especially with the lower hard block lifespan. It mitigates any real use as a quarry but keeps its utility as a log chopper :)