Overall Rating: 7.6
As a dramatic conclusion to what has been a very eventful season, this episode feels a little limp. It's...really not that interesting. It's even less interesting when you know that Odo's painful human phase is only going to last about half a season. But there are some very interesting little elements that lift up my rating.
Plot summary - enjoy, courtesy of the DS9 Encyclopedia and Lexicon!
This is the episode where Garak moves from amusing side character to seriously interesting and useful dramatic plot device. This is the moment where Garak demonstrates that he is an enemy of the Dominion and, therefore, a potential ally for the Federation in the coming war. And this is the episode that pays off the insistence by several other characters with whom we've had dealings that Garak is not to be trusted - that he'll betray you if it suits him. Garak's role in this story: first as Odo's distraction, then as true Cardassian representative, and finally as would-be assassin - is what makes the script worthwhile.
The character "development" for Odo is sadly uninteresting and will continue to be uninteresting right up until the writers say "aw f*** it...let's undo that mistake" in a nearly-feature-worthy reset button episode called "The Begotten." On the bright side, any story centered on Garak is guaranteed to have Andrew Robinson doing a lot of acting, and that can only be a good thing. :) And you do have to give mad props to the writers for throwing us a bit of a cliff-hanger with the whole "Gowron...the head of the Klingon Empire...is a changeling!!" (dun dun DAAAAHHHH!!!!) moment.
I have to ding an otherwise fascinating character piece for Garak...for not intending to be a character piece for Garak. The Odo part of this story is just...boring. They should have spent more time with Garak...showing more of the anguish that leads to his decision to try to kill the Founders. That part of the story was way more significant to the show's future than Odo's trial and eventually transformation into a human.
There's nothing wrong with Rene Auberjonois' performance, though. He and Andrew Robinson worked well together and I did enjoy his work with the female changeling. But really, Robinson steals the show here.
So...Garak breaks into the weapons control system of the Defiant bent on blowing up a whole planet full of aliens and Worf shows up just in time to stop him, onjecting on the grounds that he's violating protocol, that in carrying out his plan, he'll kill Kira, Odo and Sisko, and that such an attack would be dangerous to the Federation. The cool thing, though, is that he never protests on the grounds that killing your enemy while its' back is turned is morally wrong. This is quite a leap form the usual dogmatism of early Star Trek. A leap in a far more realistic direction.