MoP cloak effects should be transmogable - I personally would love to be able to see the effect as either attached to the cloak or unlocked as a seperate option akin to
The MoP legendary will forever be irreplaceable : r/wow
How do you feel about the changes to Corruption and Legendary cloak catch-up mechanics?
Returning to Azeroth: A Quick Guide to Upgrading the Legendary Cloak, Running Horrific Visions, Mastering Assaults, and Navigating the Corruption System - Wowhead News
Mists of Pandaria Legendary Cape Guide: Updated for 5.4 - Wowhead News
Visions of N'Zoth's Legendary Cloak - Upgrading, Stats, Special Procs - Wowhead