What it did was make a defender pay mre attention to a receiver over another in zone. If the offensive player flooded the zone, and there was a spot light, that would open up the other receivers. If the offensive player was focusing on one receiver, that player was more likey to get shut down. If the offensive player was smart, he would find the open man and not force it to one player all day. Spot Light is nice when people force the ball to one receiver all game long.
When my friends and I play OTP, we will often see someone pick the ravens or Vikings and one palyer will be the QB and he other the HB. When this happens I put Revis on the HB in the coahing menu. They will just try to force it to their HB all game long, and Revis is there all game long to swat, tackle for a short gain and pick off passes. this also makes these players quit because we kept them from cheesing down the field all game long.