To be honest, I think goal line technology was the big differentiator. People take that for granted right now, but we have taken a massive leap forward with its implementation. Now, think about how much of an impact goal line technology has had on the game. The march continues, and about 2 seconds later the referee calls a goal. The reason it works is that the decision is out of his hands.
With video replay, you can do the same. You can continue play if he referee doesn't see something, and have the 4th official whisper in his ear a few seconds later. Or if someone like Xhaka comes leaping in, while the referee is crowded, the 4th official can review and advise. Once the referee has the benefit of the information that you all have access to, he will be better positioned to make the right decision. For example, yesterday, the city game would have continued for a few seconds after Sterling was fouled, and the the referee would have stopped it and awarded a penalty with a note that he has missed something.
The whole idea that video tech will pause the game is overplayed. The ball is in play far less than most people realize. It's only about 55 minutes per game. There's 35 minutes per game when the ball is out in the stands, or stopped while Chelsea mob a ref. Plenty of time of decisions and adjustments.
