Of all the prequel movies at least episode I is a film even if a Mediocre one. II and III were shot on low quality HD cam and starred that horrible Hayden Christensen.
II and III have aged really badly because of their really cheap fake green screen made sets and bad cgi. But above all the acting is atrociously bad and so is the plot especially in episode III.
II is just unwatchable at any level. And III technically a C- but an F in terms of execution of the plot and acting.
All three suffer from unlikable characters but most strongly in II and III. Bad pacing, bad editing. Extremely sophomoric directing hard to believe its the same man who directed the original star wars, American Graffiti etc.
They were not superbly written by any means but Anakin and Padme were sort of likable in Episode I even at a poorly done level.Heroic, plucky and noble.
In II and III they are insufferable, selfish arrogant and pretty much evil people.