i'm going through watching Babylon 5 again for the second time - i previously watched all 5 seasons and subsequent movies 2-3 years ago - in preparation for the new B5 movie coming out at the end of july. this weekend i had a 9-episode marathon that finished off season 1 and brought me 3 episodes deep into season 2 and the differences, they are a-there.
first is the somewhat-subtle changes in production value. season 2 has a lot better CG - i noticed it right away the first time they showed B5 floating there in space - and even the intro sequence is a lot more professional. maybe they got more money, or they just had a year under their belt and were getting better at what they do. whatever it is, the difference is there.
then of course there's the change in commanders. now, having seen the entire series my favorite commander is Sheridan, if for no other reason that he's there the most (seasons 2-5) and i think the best of the 3 actors. however, going back and watching season 1 i did start to like Sinclair quite a bit, and the sudden change from season 1 to 2 is jarring... it takes a while for you as a viewer to get used to the change in actors, the change in styles of commanding, and i think it took Boxlightner a while to come into his own (he's pretty shaky in the first part of the season). but he does come into his own - i know this, i've seen it - and i can't wait for it.
seasons 2-4 of B5 is some of the best television around... though again, just having seen season 1 again, it was no pushover either. had Joe known that there was going to be a season 5 all along, had he been able to stretch the fight against earth alliance out into season 5 and not have to cram it in right after the war with the shadows... it would have been perfect. as it is, season 5 for me is a throwaway season, but i'll watch it again.