I have a (mild) issue with minecraft and vintage storages block system. And would like to make you consider a change (not as in a complete overhaul)
A block of sand/dirt or gravel standing by itself is realy ugly so what i propose is that a block witout support (or not enuff support) would slide to the sides (not the whole block but part of it).
An example would be insted of a block of sand it would be 12kg sand (in the form of 1 block) but if it is not supported it would split and slide so that the main block would be 4kg and each block around it would be 2 kg.
This split would depend on the material. Like wet sand would be able to hold 8kg before it would split/slide.
Some types of dirt would hold togeter better like sand with clay in it or with grass ontop would keep it's block form while dirt with sand in it would split more easily. (This could be the fertility)
Then the shovels could take a kg of the block per swing depending on the material of the shovel and if a stat system is implemented the amount could be dependent on your str stat up to the maximum the shovel material could support