People always complain about how slimefun is TEDIOUS. It's sadly true. You literally have to babysit the machine and it's annoying and requires a lotta time, that not all players have. My suggestion is to create a new slimefun machine, able to transfer items between machines. It would be much slower than vanilla hoppers (so that hand smelting is still more fast) and require some energy. The crafting should be not too cheap, because everybody would use them in thousands of copies, and not too expensive, because only high tier players would use them, and they usually play a lot and have the time to manually smelt. More tiers would make them faster. What do you think?