I tried the Mafeasance one solo. I was playing for probably 3 hours and kept getting killed at the end boss fight. I broke down and begged a guy in my clan to help me out. He was astounded that I kept at it that long solo. We got it done in the next 5 minutes once he joined me. After that, I pretty much gave up on trying to do the other stuff solo (whisper, thorn, shattered dungeon, etc.)