This was always one of my favorite episodes of Voyager, and I struggled how best to characterize it with my four ranking methods, since it flirts with nearly all of them.
But I had to be honest with myself. You can enjoy the series without having seen it, because Neelix is basically enjoying a classic Let's-Torture-O'Brien episode (a recurring phenomenon in Deep Space Nine, and even his earlier appearances in Next Generation). And come to think of it, actually, but there were a lot of Let's-Torture-Neelix, episodes, too, and this was possibly the one that defines those, the most literally life-or-death-moment story in the character's canon.
But it stops short of actually saying something about him, other than being one of his more personal experiences, since he struggles with thoughts of suicide after being revived from a near-death state (he had similar problems in the first season's "Phage"). There's talk of Talaxian culture, but Neelix only cared about Talaxian culture when it was relevant, when he really needed to. Most of the time he was defined by his ability to embrace a larger worldview than even his Starfleet hosts could manage (which is what made him annoying to some fans).
What's funny is that this recurring bout with homesickness that was the only thing that made Neelix seem at all out of place on the ship actually coincides in an episode with the emerging presence of Naomi Wildman, for whom this is a key early appearance (though she's played by a different actress than Scarlett Pomers, who would assume the role in the fifth season). Naomi is the Voyager baby, born during the second season, and thanks to rapid aging (should have been Ocampan!) a character who helped mark the progress and suggest the real toll of the ship's long journey home, where if things had developed differently would have been among the first of the second generation to handle daily operations. That's why she quickly transitions to "captain's assistant," spending less time hanging out with Neelix (an ideal father figure) and more with Janeway and Seven (mother figures).
In "Mortal Coil," however, there's little to suggest how important she'll become. She's a prop.
But hopefully you care about what happens to Neelix, too!
Franchise * Series * Essential * Character
Memory Alpha summary.