you must be new to the game.
t9 and beyond have been around for awhile, T6-9 use to be the top raids and so had the top gear, since then SE have added new content and new raids T10-13 which now carry the top gear, yes equal ilvl to augmented ironworks which btw you could only augment by doing fcob. now they unlocked it alittle allowing us to get the mats from either hunts or weekly quest.
Wod is the newest 24 man raid, and as such needed to have some relevant gear and since the relevant ilvl was 120 that means it is stronger than previous end game raid gear. but not stronger than current endgame raids t10-13.
as for previous dungeons and raids not being unforgiving... well now your doing it in 120 gear.. how about you go try with a group in the lowest ilvl gear you can enter with and see how different it is. not sying youll wipe but youll notice a difference.
as for not letting you know its more difficult.. for one its 8man teams.. in this game that means more difficult.. on top of that coil is the endgame raids, so knowing that you should assume its suppose to be hard.