All the medical dramas that have littered the airwaves for the last 20 years owe a great deal of gratitude to this show. It's success led to an entire genre of television shows being created. Shows like ER, Grey's Anatomy, House, and several others would have never been created if it weren't for St Elsewhere.
Not to mention all the actors that got their big break on this show. Howie Mandell, Denzel Washington, Ed Begley Jr, and a bunch of others. This show not only had a great cast, but the writers almost always provided great gripping dialogue to let there talent show.
Now, the series finale may have been pretty stupid, but it was a first of it's kind.