I suspect this is true of just about any well-loved series that still brings in new fans. You get to watch the reactions unfold, some similar to your own original reactions ... and some new. Plus, it's a good incentive to brush up on what you may have forgotten or at least let dim.
Good point. And one thing about B5 is that there are so many stories that weave in and out of focus that it's easy to forget something. Just another excuse to watch the whole thing again!