I love Psycho II, next to ESB it's possibly my favorite sequel (Psycho III is ok but it's more like the Psycho II most of us would have expected, it doesn't take as many chances, though it has some nice touches from Perkins infront and behind the camera).

The breather would be the Emperor scene.

We have focused so long on the good guys in peril that the bad guys walking around having a chat serves as the chapter turner.

If the Fett dropping the plans off bits could be made they would also act as Act bridges but the film need to have a punchy middle section.

There are plenty of slow passages on Endor and in the Death Star before the big finale.