It's not about the lava, it's about the batch processing of smelting material (input/output chest). The bucket will not be burned in a future update of Minecraft anyway.
Here's an idea: have people ask an admin (or do /modreq) for a lava furnace, then when it gets done have them pay a preset amount of money for it and it could be made of bedrock maybe. This would both make it hard to get, and as well take money out of the economy.
may i suggest switching the cobble stairs with brick or netherbrick? its much harder to get, and looks nicer I love it, its awesome!!!
I think this pluggin looks quite cool. If it was added, I feel it should indeed be quite expensive to make since you could lock two chests in place of having to lock the large amount furnaces that it would replace (add diamond/gold blocks to the recipe, or else the /modreq for bedrock). I would love to see this added to the server.
Do want! And making it so we have to make it out of something expensive like iron blocks wouldn't be too bad along with other blocks or something.