Sethe trinket is performing well for AS. Some priests got it and it was doing about 10% of their damage. For example dyre was able to get one and it did great on Xhul'horac.
https://www.warcraftlogs.com/reports...done&source=16
But it is a chancey RNG thing with it proc'ing with adds alive, lined up, etc etc.
So I'd agree with Yvaelle that goren + piston is the best choice for heroic.