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Yes, yes, and yes. I agree with pretty much this whole post.
My own Rocket League theory is somewhat similar, actually:
I imagine the three players on the team as playing three different roles, which I call Pursuer, Opportunist, and Defender. Most people who start playing Rocket League fall into one of these roles, and then gradually learn the other two. A good player is capable of switching roles when necessary, and a good team will likely have every member switching constantly.
The Pursuer's job, plain and simple, is to hit the ball. A Pursuer should attack doggedly, hit the ball somewhat unpredictably (if possible), and prevent the enemy team from being able do anything with it. Once he's in an offensive position, he sets up the ball for a goal...
... so that the Opportunist can shoot. The Opportunist is the wingman of the Pursuer. His job is to sit a little further back, observe the field, and predict the movements of the players and the ball, attacking when the chance arises. He's the one who hits the ball when the Pursuer loses positioning, he's the one who scores when the Pursuer sets up the ball, and he's the first line of defense if the opposition begins a counterattack. If he fails...
... It's up to the Defender. This player stays far behind his teammates, in case the enemy goes on the offensive or gets a really lucky hit that heads for goal. A Defender is not a goalie, however; rather than stay in goal all the time, a good Defender will press an offensive advantage by moving forward, probably to near the middle of the field, and counter any attempt the opponents make to create a play, ensuring that the pressure stays on them constantly.
... That's my take on how the game plays, anyway. I've noticed that I tend to play Defender and Opportunist far more heavily than Pursuer, which is interesting, because I almost always play with a friend who is unquestionably a Pursuer. Did my play style evolve from the need to work well with his, or was it just fate?