That sounds like very bad luck. 

never heard of farming green shards in NM before nor do I plan too but curious as to whether there is a confirmed efficency to do so?  Also, just glad "Wow Really" wasn't referring to Classic arena being too difficult :)

i  dont  farm  nightmare  at  all  so  i  cant  say  how  they  drop  there  but  brutal  12-3  always  seems  to  drop  loads!  

Correct me if I am wrong but nightmare campain does not give green shards. I remember a post while back asking for the reason why. 

You can't get Mystery Shards from NM Campaign. I think it's indicated on the left side when you select a campaign under "Misc. Drops". You'll find that mystery shards are taken out of the possible drops.