The increase in the size of the ore vein with increasing depth.

Since the depth of the world (as well as its height) has increased in the new update, it takes at least more time to get into the depths of the world, so why not reward this (and also revive players' interest in mining?) By increasing the amount of ore itself underground. You don't need to come across it as often as you used to, but overall, the time spent looking will pay off. In addition, it is worth paying attention to the type of ore: if we turn to realism, then metals and diamonds should lie deeper than coal, but copper and gold (like native metals) can get very close to the surface.