The Enterprise encounters a small Borg scout ship crashed on the surface of a planet with a sole adolescent male survivor in critical condition. After considering the options, Picard has the survivor beamed aboard the Enterprise rather than leaving him to die. Then a daring plan is hatched: The Enterprise could perhaps use this Borg as a Trojan horse carrying a destructive computer virus (*); when the hive returns to retrieve this drone (as they typically do), the virus could eventually spread through and destroy the entire Borg collective.
Perhaps not everyone will agree, but in my opinion "I, Borg" was, at the time, the correct turning point in TNG's Borg saga. Granted, it would mostly become a moot footnote by the time First Contact would roll around, essentially undoing the ideas put forth here (and in the season six/seven bridge, "Descent"). But at this point, going on two years since we last saw them on the verge of assimilating/destroying Earth in "The Best of Both Worlds, Part II," the idea of taking the Borg, the previously big, scary, action-movie-spectacle-generating interstellar locusts that they were, and bringing the question of their nature into a smaller, more intimate and introspective situation (albeit with questions put forth here that are definitely big ones) — well, I think that's the right choice. A new spin on the material was appropriate at this stage in the game.
This is a different take on the Borg, and a very well executed one that considers the question of Who We Are just as much as it ponders Who They Might Be. The central issue becomes not whether we can use this Borg drone — which gets the nickname "Hugh" — to destroy the rest of the collective, but whether we should, and what responsibilities we have as human beings as we make this decision. (Conveniently, the story leaves out any mention of this course of action being discussed with higher-ranking people at Starfleet Command or the Federation government. Which is just as well — this is a story that is and should be about Picard and the Enterprise — but whatever their chosen course of action, you'd think the rest of humanity would've wanted a say.)
In true TNG tradition, this is a morality play — though it's worth pointing out that there's a legitimate point of view that can argue that humanity also has a moral imperative to protect itself from a race of amoral cybernetic beings bent only on turning us into them. But when the crew no longer sees the Borg as a swarm of locusts but instead as this individual named Hugh who appears to have feelings, the moral waters get murkier. And increasingly so as Hugh becomes more and more individualized the longer he's separated from the collective. The idea of negotiating with the Borg once was assumed to be impossible, but in spending time with Hugh the story challenges this belief.
There are some fascinating dialogue scenes where people have their longstanding beliefs thrown into question. Guinan is initially chief among the skeptics ("You have a Borg named Hugh?"), but she visits Hugh in the brig and gradually realizes she has doubts of her own — and this translates into a thoughtful scene between Picard and Guinan that considers the moral implications of this potentially genocidal plan. One thing I'll say is that this story shows people's ability to actually listen and rethink their previous conclusions — something that often seems hopelessly optimistic (and, yes, possibly naive) when you look at the world we live in today.
Picard finally realizes what he must do when he has a fascinating one-on-one conversation with Hugh where Picard plays the part of Locutus. It's an interesting bit of staging and acting; Picard essentially plays the part of the Borg collective in order to see if there's the possibility that Hugh has himself become a free thinker willing to go against that hive mentality. And therein lies the genius of this story: Even without a computer virus, Hugh might still wield a widespread influence if returned to the collective, because that sense of individuality might itself be the Trojan horse.
Is Picard and the Enterprise crew foolish not to use this opportunity to destroy the Borg? I could see the argument, but I'm glad this episode doesn't argue it. Trek is, after all, built on a philosophy of optimism and individual responsibility, and the way the story ends here is the only way the writers can practice what they preach. Besides, what better way to beat the Borg collective than by having it assimilate the sense of the individual self into its hive mind? Perhaps then it is we who are assimilating them.
* The computer virus designed here strikes me as an unlikely way to cripple an entire race of cyborgs. It's essentially a paradoxical 3D image that cannot exist in real space; Data says this paradox would spread though the collective and cause a massive system failure because of unending calculations and analysis. This strikes me as a very fancy TNG version of the old TOS cliche of Kirk Outsmarting The Computer With Circular Logic; wouldn't it be more likely that the Borg, with all their knowledge, would simply conclude the paradox is a paradox and then purge it from their system?