The key to winning the West in my opinion is the ability to stop Seattle and SF from running the ball and making them beat you through the air. Not that Russell Wilson or Jimmy Garoppolo can't beat you with their arms, but those offenses are designed to run it down your throat and they depend on the running game to be successful (conversely, I think the Rams are less dependent upon a strong running game but is much more dominant with one).
To this end, the Rams have brought in players that are proven run stoppers. Robinson, Floyd, Gaines, Brockers, etc. are proven run stoppers. The focus of the offseason is refining the ability to stop the Niners' and Seahawks' run game, and I believe Staley will really help the Rams improve their ability to shut down teams' running game.