If it wasn't for the original cast and the ever entertaining Ian McDiarmid I don't think this film would be remembered as fondly as it is, in quite a few ways TPM is actually a better film.

Some of your suggestions are really great.

I'd still like to try and do my 2 Death Stars and Piett dying to save his fleet ideas out (still building that computer for a video mockup) and the Fan-O-Matic variations would take a lot of the sillyness out and change the tone to match the other films more.

The space battle needs a complete work over (explosions that actual explode rather than just cast splodges infront of the models).

I think your ship to ship firing idea should be extended to all the ship battles and if the alternate fate of the Executor doesn't work out having her bashed to bits by multiple ships makes much more sense than the silly way she goes out in the current form of the film.

What is it with the Empire and it's obsession with building gigantic structures which can be taken out by tiny ships (it worked as a metaphor in ANH but you can only take it so far)?