Homicide: Life on the Street
By 1995, serialized shows were not the norm. X-Files was the only real one and it was a trailblazer doing something unexpected.
had a lot of serial elements (so did a lot of other cop shows from that period, as well as a few years earlier). The X-Files
certainly wasn't the only serialized drama on the airwaves in the mid-90s.
Well, to be fair Cop shows already have the mainstream audiences and appeal that Genre shows can only hope for when they begin. They can go for that kind of risk factor right from the start because they have a large enough audience potential to begin with.
I'm talking serial Genre shows. British TV had been doing this since the 60s (Doctor Who) and 70s (Blakes Seven) but in the US this was pretty alien until the 90s. It wasn't even until the 2000s that it became more common for Genre shows to attempt this.
Again, this supports Berman's idea of waiting until 2000 or 2001 to go Voyager. He understood things far better than is assumed.