Eh even leaving aside the war arc interruption sports episodes are a huge
for me. It could have been worse though, it could have been the all too often employed boxing episode.
It's not really disappointing since you know going in it's only 13 eps and a movie. Think of it as a fun little treasure you don't have to invest too much time in.
US soldiers have played baseball in every war since the Civil War. A war isn't a 24/7 orgy of violence, there are down times. I was annoyed by half of the season 7 episodes before the final arc focusing on Ezri being more of a distraction than that jewel.
As for Firefly, I may get to it someday. I'm actually rewatching Hercules and Xena back from the 90's right now and have a long way to go on that one before I get bored. Then might take up B5 next on my sci-fi/fantasy watching hobby.