I've thought for quite some time that it would be useful to set the dig group level time of a node by its own properties, instead of the tool being used to dig it. This would be particularly useful if for example you want a tool to be able to dig two different nodes which are at the same dig group level, but one node is made of a material that is "heavier" and thus takes slightly longer to dig (dirt thicker than sand).
As far as I can tell, this would require a partial restructuring of the system for tools and the system for nodes, such that the nodes have their dig group level times defined in the registry entry and the tools have just the dig group levels defined. It would probably break old mods if it is implemented directly without any form of backwards-compatibility, but surely there is a simple way to enable mods to use the "old method" (when the dig group level times are defined for a tool registry entry, "auto-fill" each dig group level time to each node which is registered by the mod; if node registry entries without dig group level times are processed before a tool registry entry with the corresponding dig group levels from the same mod, processing their dig group level times is postponed until a tool registry entry is processed or the mod is finished loading; if no tools are defined for dig group levels used in a mod, a set of default values is used instead, corresponding to the properties of default tools before the change).
Is there anything I am missing, which would make this not possible to implement or complicated beyond reason?