i dont know if this has been discussed here yet, sry for the repost if so ...
in the last weeks i wondered about my very low average blocks in the marrowgar encounter. after i continuously watched my msbt incoming damage i have the suspition that Critical Block isnt working against his Saber Lash ability properly. you can block Saber Lash but i never found a "double critical block" against it after i reread some logs here and here (hit "Paste" and paste the following there:
[{"eventTypes": [1, 2], "targetNames": ["Taryn"]}, {"spellNames": ["Shield Block"], "actorNames": ["Taryn"]}]
then hit "Run"). you can see in the first log, that his normal melee swings can be critical blocked but not the saber lash. this doesnt do very much in normal mode atm but in heroic this could be a real disadvantage if you rely on Shield Block as a nice cooldown in ICC through chill of the throne.

ciao Taryn