I remember (maybe I’m imagining this) at one point on Wikipedia or Wookiepedia there was literally a list of all the OT echoes in the PT. When I was young I thought it was really cool, and I really dug Lucas’s philosophy of “it’s like poetry, it rhymes.” Apparently not everyone finds this cool, or at least, they didn’t until the ST did it too much and now, supposedly, the PT did it well.
Lucas has stated outright that the films of the PT are meant to mirror the OT. He states that instead of seeing the conflict of TPM from the outsider’s perspective of two droids, it’s the outsider’s perspective of two Jedi (but how does that make sense George, the Jedi are integral to the plot - well, the droids are too). The pairs are on a mission to help a captive young Princess/Queen (who has crucial information she needs to deliver). On their way they get sidetracked and end up on the desert planet of Tatooine, where they meet a boy who longs to become a pilot. The old Jedi master character recognizes his force potential and wants him to become a Jedi. The boy leaves Tatooine with them, presumably never to return (which ends up not being true). On the ship, the royal girl comforts the boy with a blanket. In the climactic battle, the boy ends up destroying the sphere shaped space station (with the help of R2), saving the day. Elsewhere, the older Jedi master mentor character is killed by a Darth in a lightsaber duel. The final scene is a victory celebration.
In AOTC, like TESB, there’s another galactic civil war waging, and a large scale ground battle set piece. The heroes are split into different plots. Two of the leads fall in love over the course of their story (the third lead has no love interest), their first kiss is interrupted, and right before it seems like one or both of them might die, the woman professes her love. Skywalker leaves his mission to follow a vision he has (but he’s too late). There’s a bounty hunter Fett involved. A chase through an asteroid field. The good guy ship uses garbage to getaway, and powers down the ship and hides. C-3PO ends up in pieces and R2 drags him. A Darth extends an offer to one of our heroes to join him. Skywalker loses his right hand in a lightsaber duel.
ROTS, like ROTJ, begins with a lengthy sequence where our heroes have to rescue their friend from a bad guy, who gets killed by one of the heroes. There’s a battle on a forest planet with hairy creatures. There’s a high speed chase scene in the middle of the film. Skywalker faces the ultimate test of whether or not he will turn to the dark side. In one scene, Skywalker uses his anger to best a Darth (who previously beat him) in a duel while Palpatine looks on, goading. In another scene, Anakin/Vader watches as someone he cares for suffers force lightning, then turns, lashing out at his former ally who ends up dropped down from a large height. The climactic duel is Skywalker facing off against his father figure - but the good guy is reluctant to fight. One of the final moments is a funeral for one of the main characters of the trilogy. Anakin/Vader finally puts on the mask/takes it off.
These are specific ones relating entries to their respective entries, but there’s more than that. The parental figures the Skywalker boys grew up with are killed, in ANH and AOTC. TPM’s climax actually closely mirrors ROTJ’s (lightsaber duel + ground battle with native species + space battle to destroy station), and then in both we get a pyre funeral right after and then a victory celebration. In AOTC, we get a bar scene where Obi-wan cuts off someone’s arm. Obi-wan says “hello there” in both trilogies. Anakin says “this is where the fun begins,” a Han Solo line. Both trilogies feature a prominent shot of people looking at the setting twin suns at the Lars homestead, backed by the force theme (speaking of the Lars homestead, a couple scenes in AOTC and ANH feature the same locations and even the same camera angles). Not to mention countless other intentional visual references that are hard to describe, like R2 knocking off C-3PO (AOTC droid factory and ROTJ sail barge). Plus all the things I’m forgetting.
I think that the whole “similarity” aspect of the PT helps the movies quite a bit, in many ways, giving the stories a mirror to compare and contrast to, enhancing the themes and characters at play. Ultimately, the prequels are a failure, but not for this reason, which I think makes them rather interesting. Honestly, more often then not, when the PT tries to do something different, those are the times it fails spectacularly (to pick the worst aspect from each - Jar Jar Binks in general, the forbidden romance, and turning to the dark to save Padme).
Well folks, debate away (but please, keep the debate PT-oriented).