I agree with most of the points in this post. Personally I enjoyed playing marksman/sharpshooter before it was nerfed to the ground, killing most bosses both before and after 4.0 with nightmare buff etc. I wish for a buff that makes it viable again compared to Virulence, and I wouldnt mind to add some sort of proc to make the rotation more interesting. I like the example of having Corrosive Dart being refreshed up to 1 time or something by aimed shot. I dont think Aimed shot/Ambush should be buffed to what it used to be at the start of 4.0, because of pvp balance.
Its just sad that you would choose a Virulence sniper 100% on all bossfights compared to MM/SS. Something should happen to the spec, because if you use MM in a bossfight, it is either (1) because you are missing a classbuff, (2) someone is messing around to prove a point or (3) you just dont have a clue what you are doing.