Deepslate generation mechanic

A change could be made that when lava flows over blocks of water at y levels of below 0, instead of the blocks turning into stone, they could instead turn into deepslate, similarly when lava flows over flowing water or water flows over flowing lava at y levels of 0 and below the blocks would turn into cobbled deepslate instead of cobblestone. This change would give you the mechanics to make a deepslate farm