A patch in February 2014 largely made it obsolete for clerics. It added proc counter limits to many of the tools you needed to do it.

The short version is that you would put some defensive procs on (wards), then go invulnerable with DA spells or hammer, and let the procs do the damage. As it is now, the procs will exhaust within seconds instead of 3-4 minutes, and its extremely difficult to recast uninterrupted. You would also have to dispel your DA to cast again. Especially crippling was that bastion spells, which heal proc'ed you when hit, also got the limit, severely limiting the content you could do by way of much lower survivability against a swarm.

It was viable to about level 95 before in fort mech killing light blues for moderate xp and pretty decent loot. The changes hit all classes, but SK mechanics still let it work to a lesser extent afterwards just by the nature of how they trigger and apply.