Legendary Cloak Questline to be Removed
Blizzard have announced that, from the next patch, players who have not yet started the Legendary cloak questline will no longer be able to access it. Those already on the questline will still be able to complete it and, as Valor points are going away, the "collect Valor points" part of the quest will no longer be required. When the new expansion hits ... the questline disappears completely - you will no longer be able to gain the legendary cloak and all the relevant quests will go away. If you have the cloak already, you keep it.
See the Blizzard post for more information: http://us.battle.net/wow/en/blog/15910699/legendary-cloak-quest-last-chance-black-prince-buff-extended-9-16-2014
If it were transmogable,or there were plans to make it transmogable then I would be making a serious effort to finish this on at least Joli (my achievement whore :P), but currently lfr is not something I want to do and I am not even at the pvp part on her yet...I might give it a go just for the 'I did that' brag but if I don't get it done in time, not sure I am bothered. Shame they don't scale like heirlooms really or they could make quests scale to your level then they wouldn't have to remove it at all.
It looks like, if you get the legendary cloak on an least one character, you will receive a new title: Legend of Pandaria
http://wow.joystiq.com/2014/09/19/warlords-of-draenor-beta-legend-of-pandaria-title-introduced/