I mean, saying that offscreen 20 years ago a senator secretly bankrolled a clone army, the tech required to field it, and his all of this from everyone isnt much more of a stretch than the lich king wasnt as dead as we thought and spent the past 30 years doing the same thing with new tech offscreen.
They spend exactly 0 time explaining the switch from the clone army to the imperial navy, how the republic actually functioned past "there is a Senate", and plenty of other things. To be perfectly honest, the prequel trilogy and the sequel are pretty similar. 1st movie is safe star wars content, 2nd completely ****s up and the 3rd picks up the pieces to try and salvage it.