offense (obviously) and in this type of offense you don't need incredible WR or RB talent. The WR need to be more technique oriented then athletic. Jerry Rice is the perfect example of this. He never topped the charts as an athletic beast, but was a master with technique and catching the ball.

 

Here is an exerpt from Wikipedia or West Coast Offense:

"The West Coast offense requires sure-handed receivers who are comfortable catching in heavy traffic, and the system downplays speedy, larger receivers who are covered easily in short yardage situation. One result has been the longevity of receivers in the West Coast system such as Jerry Rice, because familiarity with the system and clear signalling is of greater importance than systems that require a receiver to "stretch the field" where any loss of speed is a major liability. "WCO" systems also rely on agile running backs that catch the ball as often as they run. Roger Craig was a leading receiver for the 49ers for many years and was a 1,000 yard rusher and 1,000 yard receiver in the 1985 season. Finally, receivers must follow precise, complicated routes as opposed to improvisation, making meticulous, intelligent players more valued than independent, pure athletes. Jerry Rice's unique skill-set made him a reliable and durable asset in both Walsh's and Seifert's versions of the West Coast Offense, and he was able to break numerous NFL receiving records over the course of his career."

OL doesn't need to be amazing because passes should be coming out pretty quickly to pre-determined locations.

 

Above all else, the QB just needs to be accurate.