I don't think anyone in Synergy ever said that crit mitigation is useless Ailees. However I don't think that the crit mitigation that one or two legendary set pieces offer (you are looking at what.. 2 or 3 points then?) is gonna make a huge difference over for example VP/SoH-level gear. I understood that the progression in TSO is built on needing more fabled set crit mit gear as you get further into the raiding zones (or bringing a huge amount of healers, but that's less fun :P).
For the stuff we are working on atm (thet mainly) I really don't think crit mit is a huge issue, and when we get further in we will be obtaining more fabled set gear specifically for the crit mit.
Getting the 2nd tier legendary sorceror shoulders is a good idea though, cause 8% base dmg increase is jummie, and maybe it helps you finally beat your guilds' warlock
