If Icheb hadn't actually returned and become a fairly major character in the series, "Collective" might go down as a fairly repetitive Borg episode for Voyager. Once again drones are reclaimed from the infernal hive mind, reclaiming their own identities, however reluctantly.
As it is, Icheb, among the several pint-sized Borg to be rescued, actually does become significant, not just because he receives a spotlight episode of his own a little later, but because he's the latest passenger the crew accepts and embraces as one of its own. Sometimes mistaken for a monotone Wesley Crusher, Icheb has his own legacy to contribute, as the observer who actively contributes to the growth of those around him, the missing link, for instance, that allows Seven to move on from her remaining limitations. He even makes a man out of Q's son!
But "Collective" on its own might be skippable, except that for the series and Icheb, you need to see it to know where he came from. If you care enough to know how mundane it really is.
franchise * series * essential * character
Memory Alpha summary.