Ore Generation would have to be reworked to be a bit more like it is on RL. Most of the time, you don't find anything... Sparse single-block ore deposits near surface, but pointing towards massive ore deposit deeper underground. Branch mining wouldn't work, you'd need to actually dig long mineshafts, hoping to expose enough stone in order to find the tip of a vein, which you then start digging towards in order to mine everything out. And by veins i do mean VEINS... Automatic mining doesn't yield much unless it's a massive, MAAAASSIVE hole in the ground like the ones you see people digging in Russia and Africa to find diamonds. Actual good yields would be found more often by using TBM's', letting them run overnight, and trailing after them. These veins would not be perfectly ditributed across chunks but often span multiple chunks, and often not found for multiple chunks as well. High rewards when you find one, very low yields otherwise. Some sort of automatic processing of gravel & sand with water strainers to get low, but consistent yields would also be very welcome as a early game automatic mining solution, before you have resources to build TBM's and the like.
Minecraft would become quite a different game, however. This approach is much more in line with what Terrafirmacraft intends to become, but with more tech at the end of the tech tree.