Well, it's hardly the game that "launched the RPG genre" as CRPGs existed for years before that and were popular. At the time, Baldur's Gate was a throwback to the older CRPGs. Specifically the much vaunted "Gold Box" series made by SSI.
BG is a pretty innovative for it's time CRPG focused a strong story, characterization and malleable mechanics of the AD&D ruleset.
The sequel, Baldur's Gate 2 would go even further developing internally consistent and cohesive storytelling within an RPG that is specific to the medium of video games. As in the the conventions of the game play out exactly because it is a video game and nothing else.