So I am a die hard BM fan. Have always played the spec as my main. I have read so much about the hate with Sniper Training so I had to try it myself.
HOLY FREAKING COW! I love it. I can get up to 30% mastery and it makes the spec so much fun. I do see how the moving part is the downfall though. Simple fix would be to remove the 3 second timer while you already have sniper training up. Basically the way it is now only gives you 3 seconds to move before the buff is going to fall off regardless if you stop moving or not.