To make it harder, duh. I would also like such a nerf Also, perhaps from greg a nerf that stops you from picking lava up with an iron bucket. At least a steel bucket would be needed (of course he could just make regular buckets require steel instead and add some kind of Bronze bucket for water.
Well, actually, it's to make cobblestone more valuable. I know you can still acquire massive amounts of it from mining and quarrying, but I didn't say I wanted it to be just getting diamonds or anything. Just to make it an abundant but non-renewable resource, as it should be.