Nutshell: Not up to the first two episodes of the season, but a good show with a good argument.
When an accident allows a Jem'Hadar soldier named Goran'Agar (Scott MacDonald) to free himself of the drug dependency that keeps the Jem'Hadar masses under direct control of the Founders, he captures Bashir and O'Brien—ordering them to help him in his mission to free his military unit from the drug as well.
Well, "Hippocratic Oath" can't really live up to the first two installments of this season, but considering those first two installments what do you want? This episode is, however, another good outing, featuring an interesting twist in the Jem'Hadar, showing that they do have their own internal vulnerabilities. Given the right circumstances, this idea could show up again in future episodes, possibly as an undoing of the control the Dominion has over its military.
Although this show is not always on-the-money, it is a good premise, and the writers do capitalize on the opportunity characterwise. We again get a closer look at the Jem'Hadar and their lifestyle, which is no more than that of a 24-hour soldier. However, it's interesting to note how Goran'Agar becomes more and more able to think independently and question his service to the Founders now that he has freed himself of his drug addiction. He begins to develop his own moral structure.
Bashir begins thinking about helping Goran'Agar overcome the addiction—which puts him in major conflict with O'Brien on the matter. O'Brien, more of a hardened soldier himself, has doubts about Goran'Agar's sincerity. Besides, what if freeing the Jem'Hadar from the Founder's short-leash control leads the Jem'Hadar to go out on a conquering spree of the Alpha Quadrant? O'Brien refuses to help them. Bashir orders him to. O'Brien disobeys the orders. The result is a rather unsettling clash of these two ideals and their friendship. Kudos to the writers for threatening one of the series most well-defined friendships over a high-staked polemical topic that these two see in completely opposite ways. This is what defines the heart of "Hippocratic Oath" and makes it work.
The resolution of the Jem'Hadar plot line goes basically the way it has to go. Bashir is ultimately unsuccessful, partly because O'Brien intervenes in (well, actually destroys) his attempts to free Goran'Agar's troops. Although the overall results of the plot are not exactly earth-shattering, it is quite possible that we will see this element of the Jem'Hadar again. And the character dynamics in this episode are terrific.
A subplot featuring Odo and Worf at odds with each other on security measures makes a whole lot of sense and has a number of relevant points. It shows Worf trying to adapt to his new position and drives home the point of how differently these two characters go about doing things. In a reassuring scene between Sisko and Worf, the Captain tells him that starship officers often find it a bit awkward learning the unofficial rules of the station. "You'll fit in, Commander," he tells him. "Just give it time."