A 12mm drop in running shoes is considered relatively high. It provides more cushioning in the heel and encourages a heel striking and heel-to-toe transition. While some runners prefer this level of cushioning and support, others may find it less conducive to a natural footstrike.
But while 12mm drop is considered too much by some runners, thousands of others come back to the 12mm Brooks Ghost and Adrenaline GTS year after year.