Absolutely right.
I've got probably hundreds of pages of notes on my computer for possible stories for a prequel rewrite. Everything from going Flash Gordon with Obi-wan as a Hans Zarkov character to Anakin's wife being a Joan of Arc character having visions of the good side of an extremely schizophrenic Anakin/Vader inspiring her to begin the Rebellion. Then there are the more reasonable stories, the ones that cleave close to what the audience would expect from watching the OT.
The problem with making a story about Anakin Skywalker is that the OT played off of the fact that Luke's father was a mystery to Luke to make him fearful. If an audience knows exactly how Anakin was seduced to the Dark Side, no matter how it happened, it would lessen the impact of the OT. For you only fear what you don't understand, and Luke must travel the path to becoming a Jedi not knowing if his actions are a mirror of his father's actions before he fell. In a way, Anakin's story is already told through Luke's journey in the OT. So making Anakin's story the focus of the Prequels is frivolous.
Obi-wan's story is also unfitting as the focus of the prequels, for we already know exactly where he ends up at the end. Also, telling his story requires knowing Yoda and a lot about the Force, making the films not work if they were to be watched before the the OT, or in proper numerical order.
In the end, I think that the prequels can't be about the Jedi or the Force, because to do so would simply repeat a lot of the OT. It would have to be a smaller story, with a main character whom we don't know, with a goal that doesn't have to do with doing something we already know the fate of. For example, having a story about someone fighting for either the Republic or the Separatists will inevitably end in tragedy, so if you want an uplifting tale, that's out.
I'll probably be altering my Stars of War thread soon, so you can read there what I have in mind for a "rewrite" of the prequels. I say rewrite because there are way too many ways to rewrite the prequels, and with a focus on entirely new characters and situations during the same period of the Clone Wars, the existing prequels and EU need not be discarded to have a compelling origin story for the Star Wars universe.