Actually, overuse of macros actually has the potential to lower dps. It just makes things more efficient some of the time. Lets look at an example.
If I have a macro bound to my opener that also pops my relic when I am actually not trying to score a kill but just controlling a player would be a waste, similarly opening on a mob prior to an ops wide CD being used would cause a desync of abilities. That being said, when that opportunity comes up, not having to mash three buttons at once to blow your load doesn't decrease skill, I already know what I am going to do, it just allows you to properly line things up.
Similarly, if you think targeting in this game is anywhere near acceptable, I am at a loss for words.