I generally try to avoid having to Swiftcast Shadow Flare, and try to use the time that the tank is positioning stuff to set it up, since before then, things may get hairy with aggro if you start to DoT too soon. I mainly only do it when it would otherwise get in the way of DPS time.

I also find myself not Festering during 'AoE Time', as I usually want those charges for more Bane. (phase 1/4) I do find myself doing both on Soldiers, because it is the only good way to get some damage onto Knights, but Soldier is also my primary target. Sometimes I opt to Fester instead of Bane if I am not (or cannot) going to Contagion.

Tri-Disaster is mainly the filler between DoT sets during 'AoE Time' because of Bane's cooldown. I usually always Miasma2 before Bane, but only if I am going to Contagion it first.

Also, I find that at the start of an AoE rotation, that telling Garuda to Aerial Blast, then Steady to get ready for the imminent Contagion can vastly speed up the process of getting to Bane, not to mention I find it tragically annoying when I am spamming Contagion and she is in some wacky cooldown loop doing more Wind Blasts than I want.