The little orange ball droid means it's not about R2, and so it is not Star Wars.
I will now point out the forest that SW geeks can't see for the trees. Lucas didn't have the sci-fi background to make SW up all by himself, nearly all of it is adapted from Isaac Asimov's Robots and Foundation stories.
The Robot novels centered around R Daneel Olivaw and R Giskard. 3PO and R2 are exact analogs of these. Olivaw is built to act like humans (3PO) and Giskard has psychic powers (the force) that allow him to affect human thought.
To quickly obliterate ALL doubt that the droids are the main characters, I refer you to the opening of SW4. Who is on screen first? R2. Who speaks first? 3PO. Fast forward to the end of SW5. The second-to-last close camera shot has R2, 3PO, Luke and Leia. But the very last has only R2 and 3PO with a medic droid behind them. Forward to SW6. Who is front and center in the last shot? R2. Everyone else well in the background. On to SW2, who speaks first? R2. Who is last on screen at the end? R2 and 3PO - even at Anakin and Padme's wedding they are placed more prominently. SW3, the camera first zooms in guess-which-character who speaks first. QED.
Now, 3PO's similarity to Olivaw, and of the force and Jedi to the Second Foundation are obvious. There's hyperdrives. There's a city covering the entire capital planet. All the "good" droids serve humans and never harm them, like the 3 laws say. But R2's similarity to Giskard is more subtle and takes a bit of explanation.
Giskard, like many of Asimov's robots, walked a tricky line balancing the 3 laws when they conflicted with each other. His ability to tweak people's minds can harm them so he can only justify it when it's somehow for their own good, i.e. protecting them from greater harm. R2 has the exact same hero complex, selflessly saving the day at every turn. He also manages to be near every important character at critical times in their lives - Anakin, Amidala, Luke, and manipulating them all the time.
R2 is so sneaky even the viewer doesn't catch him. Luke told him to stay with the ship on Dagobah - did you notice him eavesdropping outside Yoda's window later? Not just eavesdropping, but tweaking Yoda's mind to make him agree to train Luke.
Absolute proof that R2 is force-capable occurs a few minutes later when BOTH he and Yoda sense and react to Luke's adventure in the dark side cave. R2 whistles. Yoda says nothing. R2 sensed what happened. R2 has force powers beyond all doubt based only on that one scene.
R2 is standing behind Anakin when Obi-Wan convinces him to accept his accolades from the senate - Anakin subtly makes an R2-assisted decision to seek power at that moment.
R2 distracts Vader to shoot at him first before destroying Luke's X-wing. He does this also to disable himself so he doesn't violate the 1st law while Luke kills thousands of people.
This post is already too long to list all the instances of R2 force-waving people's minds. So I will finish by saying WHY. Star Wars is on the surface a kids' movie, all graphics and spaceships and robots. The deeper and Asimov-free theme is slavery - droids are slaves, living creatures free, and Vader is both. Nobody got that, so Lucas made episode 1 overtly about slavery, but still nobody got it.
R2 is, on the surface, an archetypal "good" slave - selfless and heroic. The viewer takes him for granted, and despite his prominent role in all 6 films - including center stage in the important shots mentioned above - they still consider him a supporting character because of his small stature and apparently servile role. For over 30 years their own class prejudices kept them from seeing R2 winning at every turn and always getting his way, and standing triumphant and proud at the very end. That is a very clever commentary on the viewers themselves and is the genius of the Star Wars films.
