Yes you do more DPS but it does reduce the efficacy of Sharpshooter nonetheless. Sharpshooter takes time to tick up. With a 1H Xbow and the correct gear I was at 4.88 Attacks per second...
I attack almost 5 times in the 1 second it takes for sharpshooter to tick up another 3% crit.
However, if I crit in the middle of that, Sharpshooter resets.
1H Xbow gives you a 10% chance to crit (with Archery skill) So at 4.88 attacks per second I am almost gaurenteed a crit (10% is 1 shot out of every 10... in 2 seconds I shoot 9.76 times)
So.. Sharpshooter never gets to give me much of a bonus on my crit chace.
What he said about IAS reducing the effectiveness of sharpshooter is correct sir.
I don't think you know how Sharpshooter works.
The effect of Sharpshooter's crit hit chance stacks don't fall off after your hit, they fall off 1 second after the crit takes place.
Meaning if you're attacking 4 times a second, you still have a chance for those other 3 attacks within that 1 second to take advantage of the sharpshooter stacks.
So IAS is not reducing the effect at all - you're getting the same effect if not more of an effect, because you can get more attempts to crit with the stacks within that 1 second period.
They designed DH with attack speed in mind - and Sharpshooter as well.