Keep in mind that B5 was originally pitched to Paramount and they turned it down, only to hold on to all the pitch materials and plagiarize them to make DS9.

The first two seasons are pretty rough by today's standards but the acting isn't any less hammy than TNG of the same era. Season 3 is where it really gets into the swing of things and 4 is amazing, not least because getting told the show had been canceled led to them pulling out all the stops to wrap up every major plot in one season.

Ironically actually speeding things up like that led to such a ratings comeback the show got surprise renewed at the last minute, which is why season 5 is noticeably much poorer than the rest. The one exception being the series finale itself.