From the Shadow Priest sticky:
Singletarget:
http://i.imgur.com/uAkw5gC.png
Heavy movement singletarget:
http://i.imgur.com/n1SLlu6.png
Two targets:
http://i.imgur.com/nF8fQbD.png
Heavy movement two targets:
http://i.imgur.com/vVNEBDk.png
For Singletarget the Oakhearts Gnarled Root > spiked tongue > twisting winds (care, only if the enemy stays within the AoE) > plaguehive (considering all 880 ilvl)
For 850 Shock is better then twisting winds and plaguehive HC versions, and only a bit worse then the 2 hc trinkets is a 850 Root and a 840 baton.
And sorry for you, but it looks like bough of corruption is one of the worst trinkets for us, even the Mythic version gets beaten by nearly any other trinket.