I'm super late to the party, but here are my two cents:
7. Attack of the Clones
This one shares all of the problems of the prequel trilogy - wooden acting, stilted dialogue, and an excess of all things computer generated - plus it adds one of the most loveless and awkward romances in cinema history. With zero chemistry between Christensen and Portman, it's impossible to believe in or root for their relationship.
6. Revenge of the Sith
Sure, it's more energetic and more operatic than AOTC and TPM, but Revenge suffers from some serious issues: thin characterization, feeble acting, overproduced action set pieces, and, most disastrous of all, a main character who just isn't very engaging. McDiarmid livens up the proceedings as a deliciously evil Palpatine, but it's not enough to save what should have been the linchpin of the entire saga.
5. The Phantom Menace
Menace is a mixed bag. Jar-Jar is obnoxious. A young Anakin is annoying. Most of the characters have no personality. There are dozens of plot holes and contrivances. But there is some decent storytelling at work here, and some surprisingly effective action sequences.
4. The Force Awakens
Having seen this twice now, I might rank it as high as third. I'm no fan of J.J. Abrams, but he performed admirably as caretaker of the series. TFA brings Star Wars back to its pop entertainment origins with some spectacular action and the same mythos that made us all fall in love with the saga decades ago. The new heroes and villains are refreshing and interesting and the older characters are folded in to the mix seamlessly. The biggest problem: the script relies so heavily on hitting the beats of A New Hope that the movie often feels like more of a remake than a sequel.
3. Return of the Jedi
Jedi has a few minor problems, including a familiar plot and some overacting, but overall it's a spectacular entertainment. While director Richard Marquand doesn't capitalize on the emotional cliffhangers from The Empire Strikes Back, he does show a deft hand with some thrilling ground and space warfare. Technically and visually, it's as impessive as any movie in the saga.
2. A New Hope
Yes, Geroge Lucas owes A New Hope to many other works of art - Flash Gordon, The Hidden Fortress, and the Dam Busters, to name a few - but never before had a filmmaker combined the themes and visual markers of science fiction, samurai movies, dogfight sequences, and world mythologies so coherently (and so profitably) than in the premiere Star Wars movie. Visually inventive and emotionally resonant, Star Wars changed the landscape of American cinema forever.
1. The Empire Strikes Back
Even with all the creative energy and guidance than George Lucas gave to Star Wars, he never truly unlocked its full potential. But two other men did: Irvin Kershner and Lawrence Kasdan, who directed and co-wrote Empire respectively. What they brought to the saga was a developed sense of internal conflict and an effective appeal to the emotions of the audience. The characters in Empire aren't simply archetypes; they're living, breathing, conflicted people trying to come to terms with a world at war. The special effects on display are phenomenal, and the action scenes rousing, but the movie is great because of its character arcs: Han and Leia's growing affection; Luke's aborted training; and Vader's obsession with finding his son.