I had much the same problem as you with my Thugs/Poison MM (now 50). Mostly it was the end drain that was frustrating me. This was one of my first few 50s and my second 50 on vill side. When it comes to MMs I'm still very newish.
So I searched the forums and found Poison Pill's guide for thugs/mms. I built my toon exactly like the build shown in the guide and it's pretty good. The build is only an SO build though and I'm not sure where to go from there. As far as IO sets go.