Don't get me wrong, overall liked DS9. It showed a unique side of Starfleet and how everyone didn't get along in the galaxy like TNG would have you believe (more or less) but their "End justifies the means" attitude shifted TNG's moral base attitude (which was probably their goal to began with).
And which, honestly, was probably not a bad thing--and closer to the sometimes painful choices and more complicated morality of the original STAR TREK.
Remembering Kirk deciding to "bend" the Prime Directive by arming the locals in a "A Private Little War"--or letting Edith Keeler get hit by a truck in "City on Edge of Forever"--or even seducing Lenore Karidian in order to expose her father's atrocities?
One could argue that DS9 was just getting back to the less "utopian" morality of TOS where Starfleet captains couldn't always keep their hands clean.