Far be it for me to tell anyone how to set up their masteries but you really should consider moving points around. Crit damage does way more than regular damage and precision is really a must have imo. Really, consider moving all the points prior to precision and cruelty to 1 and exploring beyond into the second half on offense. If you don't have those open yet I'd strongly recommend working on that. Just my .02. Take it for what its worth.
You have quite a few bleeders, deep wounds would prolly be a nice investment. Assassin is expensive but I'm a big fan. Glass cannon is a must imo. The loss of health is nothing compared to the extra firepower you'll get. Some don't like the lost health and that's legit. Just don't get hit lol. I wouldn't do suicides with your roster...yet. somewhere down the line you may want to though. Best advice, pick some champs to center your masteries around and go from there.