* There were major continuity problems and ridiculous plot holes large enough for a truck to go through, things a child could detect after reading the script, but that's how the prequels are.
* Not enough Vader. and I mean the REAL Vader. After he gets the suit the movie ends in about 2 minutes. We should get at least 15 more minutes of film after the suit.
* Cut scenes that SHOULD NOT be cut. The scene in Dagobah and Qui-Gon's scene SHOULD have been in the final movie. There was absolutely no reason for removing them. Pace problems? Those scenes were in the final 5 minutes! By cutting Qui-Gon's scene, he cut from the SW saga the whole explanation about the Jedi spirits!
* Anakin's fall to the dark side is too drastic and not well played. It seems like GL was aiming for a subtle change, but suddenly he saw himself at page 100 on the script and decided to just make him go to the dark side like that *snaps fingers*. Also, Anakin becomes Palpatine's servant too easily. But then, if you think about it, there was NO way to make that character go to the dark side in a 2 and a half hour movie...
* The middle section feels rushed AND slow at the same time, and that's not good. It suffers from the same problem as the prequels: two-sided dialogue being rapidly intercut by... a two-sided dialogue. And again. And again. Headache material here, folks.
* R2D2's absolute power, with oil and jets. They did an excelent job erasing the droid's memories, as R2 also forgot his abilities...
* Acting. While ROTS has the best actings in the prequels, it still have some horrible moments. Natalie Portman's acting in the first half of the film, Ian McDiamand going a little bit over the top and changing his voice characterization in the middle of the scenes (later dub problems, perhaps?). Hayden's every scene. Samuel L Jackson and Ewan McGregor, when they are forced to act to absolutely nothing (you can FEEL the greenscreen on their acting sometimes).
* While the SFX were not as disturbing and horrible as the previous prequels movies, it is still very annoying.
* J.E. Jones horrible job as Vader. Even though he had three lines, and one of them was "noooooo!", he delivered them like he didn't care.
* Hayden in Vader suit, acting as a fool. DAVID PROWSE should be there. He deserves it.
* Padme's death. She gave up living and died of a broken heart? What is this, an early Shakespeare play? A Byron poem? Absolutely ridiculous.