First, the subplot: it is so forgettable that the other reviews on this site don't even mention it. Huge anamolies appear out of nowhere (oh, wait, they're from subspace, oh wait, they're from a layer between space and subspace). They emmitt so many gravitons that Tom has Voyager riding the waves like a surfer, yet current 20th century science is mysteriously unaware of the phenomena, even though it is happening in our own galaxy. Right now we're trying to detect gravity waves from across the universe caused by two black holes orbiting each other. You'd think something that gave off these kind of gravigy waves in our own back yard would be easy to spot by comparison. Of course, this series doesn't have much use for science except for providing techno-babble jargon. All kinds of ship's systems are damaged or go offline, yet Janeway decides to hang around the area in the interests of science, even though just one thing going wrong would strand them in space forever, since there's no Federation to save them. Finally it's determined that Tom make an extremely dangerous mission collecting plasma so they won't have to eat goulash for the fifth day in a row. Go back and watch again, this is really the reason he does it, no kidding. Of course, in the inevitable ensuing rescue, they loose another shuttle. What is that, the sixth or seventh, I lost count? How many shuttles did the Voyager have initially?
Now for the main plot: Once again the doctor is allowed to screw around. Never mind that he's the second most important member of the crew. Never mind that only a few episodes earlier he almost destroyed himself with his own tinkering, never mind that the only hope of diagnostics for the doctor was sacrificed to give the doctor more capacity.
I don't really want to see episodes about family life. There are plenty of shows out there where I can see this all day long. I watch star trek hoping for something more.
I don't know which of his two families was more cardboard. The first was sterotypically good, the second stereotypically bad. Neither was believable. Belana programmed in some random factors, so "of course" it makes sense that the next day his daughter ends up dying. Yes, that happens in my family every week or so, too.
Why was the doctor so attached to the family? It was totally unbelievable. In a couple of days he comes to care for these "artificial" people to such an extent? Why? And why did they care about him? Because they were programmed to. So why would some people see this as a tearjerker? There are so many layers of "artificial", how could it ever seem real to someone? I think some people just like to cry.
Finally, when you introduce a subplot, it seems to me there should be some reason for it. It should play off the main plot like a countermelody. Some type of insight should be provided, either through similarity or contrast with the main plot. I see no evidence of this at all. Instead, I think the writers thought, boy, this family oriented episode is going to bore the sci-fi nerd, so let's through in some pseudo-scientific stuff with good special effects to keep his interest.