The problem with remaking B5 is that the story is so integral to the series. I don't want to see them just recreate the plot of the series, I'd want to see something completely new that makes the hairs on the back of my neck stick up like they did when I watched it for the first time.
Yes, we had a similar thread here about six months ago, and I made a similar point. Remaking B5 is a fundamentally different endeavor from remaking classic BSG or classic Trek. The question is, what exactly is it about the original that you like, that you're trying to remake? In the latter cases, you're rebooting the characters and the premise into a new story or series of stories.
But in the case of B5, what drew many people to it was the particular story that was being told. You're going to redo that very same basic story all over again, in 100+ hours of TV spread out over 5 years, but just update it in certain ways? I find it hard to believe that you'd be able to find a group of writers who are willing to write about 6000 pages of scripts over that length of time for a story that is not their own. I really don't think it would work.
You also have to keep in mind that a lot of the drawing power for arc-heavy shows like nBSG and Lost is the fact that viewers want to keep coming back to see how the story will unfold. If they already know the basics of the story, they're not going to keep coming back for five years in the same numbers. There isn't going to be the same level of online discussion and speculation about where the story is going as there would be for something original.
The only way I can see a B5 remake happening would be if it really was "B5 in name only" where someone takes the concept of "UN in space", along with some character reimagining on some of the more popular characters, but then does the show with a completely original story which bears virtually no resemblance to the original.