Stoneskin is great to use on DPS so if they get hit by something you probably won't have to heal them same if they manage to pull aggro for a few seconds the Tank can get it back without them being squashed instantly.

I don't really get the hate for fluid aura it's a good emergency skill sure if a Healer was spamming it for no reason fine yell at them but if the Tank loses a mob because they are not holding aggro on all mobs and it decides to take a stroll and say hello to me then i'd much rather use fluid aura to either push it back towards the Tank's position or push it out the way and sleep it so it can be dealt with later. Having the Tank move is not something i enjoy especially when to pick a mob back up they want to run at me and bring all their friends with them who them spam their AoE effects in my face. Amusingly some Tank's when i avoid said AoE's are like "omg don't run!"