"need" was a poor choice of wording. Obviously including all of these is not strictly necessary (nor the existence of the PT). This is intended mainly as a list of things I have seen other critics state were improperly explained in the PT, and the difficulty faced in actually explaining them properly in only 3 films.

Ideally, I would like to see all of these events told because they can be told in a good, coherent story. I'm all in favor of leaving some prior events to the imagination, for example where Yoda and the Emperor came from, as any attempt to explain their back story tends to corrupt their majestic characters.

A lot of what leads to the Clone Wars could be very boring (e.g. taxation of trade routes), which is why I would like to start it basically at the first battle. I agree the insertion of a love story is not needed at all, but it mirrors the OT very well and I think there is a hint of it when we hear of Leia speaking of her mother in ROTJ. Nor do I think we need to explicitly see Palpatine's manipulations to gain power. Hearing his voice blare propaganda would kind of ruin it for me. It could be handled with much more subtlety.

Agreed. I think the events of RotS could be made into three films and work just fine. Nothing we saw before that really matters and besides that it was all boring.

I have considered that idea myself. Most of what we expected to happen in the PT was packed too tightly in ROTS, but I think it would be too diluted if spread over 3 films. We see Anakin as a Jedi doing great things as a pilot in battle. Frustration with the Jedi and the war leads to dark thoughts. That's maybe one film. Then he turns in the next, hunts Jedi, and gets put in the suit. That's another film. If you try to stick in a third film you'll end up in territory where you are struggling to decide what to put in it from the above and still be coherent.

Perhaps I want a prequel story that explains too much, but hopefully it leads to a discussion of what should and should not be put in the story.