I think there's a trope for that and I think it refers to the Idiot Ball.
I'm now thinking that there's an idiot ball trope in each film as follows, counting prequels:
I: Jar Jar Binks is the personification of this trope. No holds barred.
II: There's an idiot ball in the Battle Droid Factory sequence, as there's a ton of chances to get Padme killed there.
III: Anikin's reckless flying at it's peak at the entire beginning of the film. There, I said it.
VI: The entire aftermentioned Death Star sequence in which the Empire had the plans, but was under their noses.
V: Vader not knowing that the persuit for the millenium falcon was all for naught as Luke was on Dagobah most of the film.
IV: The battle of endor is the biggest one. Why? Ewoks. If the Empire hadn't slaughtered the residents, then the rebels wouldn't have won.
Also, my dad claims George Lucas had an official retirement, although everyone saw it comin'. Qucikie, can I have some confirmation on that please? I also heard that Lucasfilm LTD. is at the hands of someone else.