Netsgunt, i think it was removed because it is protecting from physical damage, rogues couldn't have that and they had it removed. But they can still use Serenstum against magic.
So ya i would love to see that recipe in game, i'm a crafter and love to have all the recipe on the proper toons.
They should put it back and even the other recipes level 50 for gear that were removed also. There is no point to remove recipes from the crafters and especially of all the effort put into crafting.