If Jackie, Sr. were kept alive longer, it would have muddled the storyline for Season 1. Jackie's death dovetailed with Junior's feud with Tony over Comley Trucking, and Junior's dangerous reactions (killing Brendan Filone, mock executing Christopher, threatening Tony).

The death of Jackie and the resulting power vacuum helped amplify the tension between Tony and Junior. For only being the third and fourth episodes of the series, I think it was a good way to keep up the suspense for a new viewer.