As for the Piett turning against the Emperor (I think he would never turn against the Empire, just the crazy wizards who keep killing his men) I thought of having him seal the bridge by bringing the blast shields down on the corridor sections.

To do this I thought it might be fun to pinch one line of dialogue from ST:TMP, "Seal off the bridge" (make it sound like it's some unseen officer) so the Shat himself will actually be in a Star Wars movie (the legend didn't get to be in the latest Star Trek movie so why not go one further).

You could have a shot of Stormies on the other side trying to break through to retake the ship bookending the scene in TPM where Qui-Gon tries the same thing.

We can but dare to dream.