*Two words: missile swarms.
*Luke would do a lot more screaming.
*All the important stuff, like Ben's death, would be repeated three times.
*Vader would be at least eight feet tall.
*X-wings and Y-wings would transform, and then combine to form a more powerful craft.
*The Death Star's super laser would have an even flashier charge-up sequence.
*The destruction of Alderaan would be preceded by idyllic ground-side sequences. Then everyone looks up, and BOOOOM. (cf Hiroshima)
*When Luke lines up on the exhaust port, he hears Ben's voice. Everything freezes, tight clasp on one of Luke's eyes as the background goes black. "Luke. Trust your feelings."
*Yoda would look much like Happosai.
*Fans would draw pictures of a naked Luke and Leia embracing *after* their parentage was revealed. In fact, it might not be revealed until after they'd slept together (cue the angst).
*Jabba the Inju would get a lot more, um, friendly with Slave Girl Leia. (FAN SERVICE!)
*The Emperor would be even taller than Vader.
*The Ewoks would be even cuter.  (Eeeeeee...)
*Lando and the Falcon would be destroyed, probably accompanied by a flashback with lots of cherry blossoms.
*Han Solo, being the epitome of American Power, would be blond, carry around a HUGE gun, and scare small children.
*Alternately, Han would wear an eye patch and cape. (and the Millennium Falcon would have a poop deck...)
*The Mon Calimari would have ships that heavily resembled units from the various Darius games. (Giant mechanical FISH!)
*Luke would have black hair, and be a lot more negative.
*Light sabers would be replaced by katanas or Chinese long-swords that would glow so you could see which was flashing against the black background.  The swords would have to be metal, so that injuries could be emphasized with gushing blood.
*Chewbacca would have horns, although he might otherwise resemble an upright Mugi.
*The Emperor would have tall spiky hair and little bits of things would float upward in slow-mo when he zaps Luke.
*Lightsaber scenes wouldn't be 9 (counted!) per 6-hour trilogy, but per half-hour episode.
*The AT-AT would have claws. BIG ones.
*Vader would still be Luke's father, but we would have known about it waaaaay before Luke did.
*Luke's uncle and aunt would really be alive!
*The sand crawler would have flown.
*We'd see the Sarlac's full body.
*Leia wouldn't have a band of surgical tape constraining her generously sized breasts in all three movies except for the Metal Bikini scene.
*For that matter, Leia wouldn't have been wearing a Metal Bikini, either.
*The Rancor wouldn't have had a big bold black outline, but it would have drooled MUCH more.
*The AT-ST would have been either arm less and rounded or armed and squared off, not arm less and squared.
*Imperial pilots would have been cloned from the very beginning.
*Every time Vader tells some fool that he's underestimating the power of the Dark Side, the bystanders would mutter "Sugee!"
*The music and soundtrack would be much worse and less orchestrated, but have singable lyrics.
*Greedo wouldn't have been the only one with blue hair.
*There wouldn't be Imperial-class Star Destroyers. Super-class Destroyers would be the *very bare minimum*.
*The sound of the Force would have been "DONNNNG!"  (a la Akira)
instead of "WhwhWhwhWhwhWhwho..."
*Three words: Super Deformed Stormtroopers.
*Princess Leia would wear a sailor suit...and she would sing.
*Vader wouldn't have to squeeze air to kill a guy with the force. He would just touch him and tell him "You are already dead," followed by gratuitously vile explosions.
*Luke's aunt and uncle would run a dojo instead of a farm.
*The Millennium Falcon would sport a big skull and crossbones.
*Luke wouldn't have to use a rope to jump across a trench. Anime heroes can jump as far as they want to.
*Emperor Palpatine would have a daughter. In an amusing mix-up, Luke would be betrothed to her.
*Bandai would make kick-ass toys.
*R2-D2 would be cuter...and he would fly.
*The explosion of the Death Star would be shown with a sequence of watercolor paintings.
*C-3PO would be a girl robot...with the hots for Luke.
*People would actually drink beer in the cantina.
*Luke would not build his own lightsaber. He would have to win it from a demoness who has been imprisoned for thousands of years... and who has the hots for Luke.
*Obi Wan Kenobi wouldn't disappear when Vader cuts him down, he'd get sliced in half. It would just take him a couple of seconds to figure it out.
*There would be a LOT more walkers.
*X-wings would have cool heads-up displays.
*Emperor Palpatine's legs and lower torso would dissolve into a mass of cables and merge with the new Death Star.
*Did I mention Princess Leia's sporty yet feminine powered armor?
*Speeder bikes would be replaced by monster-sized racing cycles...with lasers.
*Boba Fett would have a bigger part.
*A nemesis TIE fighter pilot would defect...and have the hots for Luke.
*Luke wouldn't agonize over Vader being his dad until AFTER he killed him.
*The American voice actors would be crap, and the subtitled version would be more expensive.
*Series titles would be Star Wars, Star Wars Zeta, and Forever Star Wars Double Zeta. People would argue interminably about the time line conflicts.