Well the thing you have to consider is that under Rodenberry, Startrek was all about the macro scifi aspects. It was about the Q, the Borg, the Prime Directive, Data's search for humanity, these sorts of things. The crew and the ship were just there so that these concepts could be explored they weren't supposed to be realistic.
I don't think Rodenberry ever cared about the details of how the ship actually ran or anything logistical like that. All he thought of is what sorts of technology or phenomina could be out there and what major implications could they have.
It's episodes like that one where that planet erases all of the crew's memories because they have a custom of wanting to be left unfound by other aliens, but it doesn't work because they leave too many clues behind and human nature is to try to unravel mysteries. That was Star Trek. What did the aliens look like when they finally encountered them? I don't remember but I bet probably like humans or they said they made themselves look like humans to communicate or something like that.
The show didn't care about particulars, it just wanted to tell a story that explored a concept.
Now BSG, that's a totally different animal. That's a show that is all about the characters, not really the concepts. So, if they want us to relate to those characters and invest in them, they have to put them in a much more realistic take on the scifi situation so that we can imagine what it would be like to be there and be convinced enough that we understand why the characters do certain things or whatever.
Why I think Voyager sort of sucked where as Next Gen doing the exact same thing was great is that Voyager's concepts where dumb, uninteresting, and poorly written in almost every case where as TNG only had that problem for like 1 or 2 seasons. Also it had better actors over all. Even Marina Sirtis got decent towards the end, you know when she started wearing a uniform again and I think people like Patrick Stewart and even Levar Burton were almost good right from the get go.
I think the only people I liked on Voyager were the Doctor (He was good in China Beach too), suprisingly Tom Paris by the end, Seven, and to be honest I actually liked Neelix and Janeway by the end of the show too as much as that makes every nerd on the Internet think I'm an idiot. But to be perfectly clear, I always liked Neelix in concept because he was what many of us here seem to think the show needed a lot more of, Delta quadrant natives as new crew members and also, I feel he started playing the part really well towards the end of the series.
Now Janeway, her writing had highs and definate lows, but the highs were never enough to really make me like her character. BUT, I feel her performance of what was written for her was almost always good. Same thing sort of goes for Tom Paris too. He was a pretty goofily written character most of the time, but the actor made it work in a way that made him likeable. In stark contrast, I feel like Harry Kim was the opposite, a fairly real seeming and interesting character for that show who was rarely performed well.
