I've set up an assembly line for wood-burning, inserters recognize the wood as a fuel source, but not a burnable resource for the smelters. The inserters will load the wood as fuel, but I have to manually load the wood into the resource slot for it to get converted.

Any chance this can be fixed so that it's recognized as both?

I had this problem too at first, but I believe that if you load a fuel source like coal first instead, it will recognise the wood as smeltable. If this does not work, the old way of making charcoal you can enable in the settings was explicitly designed to counteract this.