the story: The crew bond while exploring the Delta Quadrant version of weird space phenomena.
what it's all about: At first blush "The Cloud" seems like a pointless franchise template episode that has no business being done in a Voyager context ripe for bold new storytelling. But the premise of the series was always about what it would be like to be Star Trek with no safety net sort of like the nebulous state of the backdrop during the original series, when the concepts of Starfleet and the Federation were in a constant state of flux and development, and anytime anyone else from them showed up it only served to prove how much Kirk and company stood out from the pack, and were in a sense isolated. Janeway really only codified that concept, in a lot of ways.
So when she decides to explore weird space phenomena, it's not really just a matter of deciding to explore it, but an occasion for the crew to decide how much of typical Starfleet business they're going to do. Fans thought this was a waste of time, but in the grand scheme of things no matter how often the ship stopped to look at something there was still a long journey if carried out in the original estimate no one but maybe Tuvok and the Doctor would be around to see completed satisfactorily...The idea was always to find shortcuts, which was why episodes like "Prime Factors" (later in the season) happen, which couldn't be done if all they did was follow a single course toward Earth.
Ipso facto: they would have to behave like a Starfleet crew, and so episodes like this would be necessary to further develop the concept of the series, which along with "Parallax" serve to flesh out the premise laid out in "Caretaker."
And besides, "Cloud" gives the crew a chance to bond, see how they function practically together, now that they've begun to settle in. This is the episode where Janeway famously declares, "There's coffee in that nebula," which is about as Voyager as it can get. It also features the debut of Chez Sandrine, a holodeck program that was kind of Deep Space Nine's Vic Fontaine before there was a Vic Fontaine, a standard period setting where the crew could hang out on a regular basis. Of course, there's no Vic equivalent in Chez Sandrine, but it's still one of the signature elements of the early series.
franchise- Another episode casual fans will probably find difficult to appreciate.
- series - Helps flesh out the premise and how it functions on an ongoing basis.
- character - This is an ensemble episode, which helps demonstrate how effortlessly Voyager did these.
essential- The McGuffin at the heart of the episode kind of drags down the proceedings, and there's no single character to rally around.