Like, I, Robot, the Foundation series is just a bunch of short stories, but with a killer plot that threads them all together over vast expanses of time. With all the jumps in time I can't believe that you could fit the greatness of those books into 120 minutes of film.
For example, in Bicentennial Man I think the jump cuts were written and edited well, but there wasn't enough time to develop the characters and so they have to be one-dimensional and you are forced to identify with the main character. In Foundation, there are no main characters from beginning to end (Seldon's recordings?) and so all the characters will have very little time to impress you.
And it's not edge-of-your-seat type stuff so a movie trilogy wouldn't work like LOTR did. So the only recourse would be to focus on a single storyline (or two) and ignore the whole thread of time. Unfortunately, the big picture is what makes those books great. I would think the best way to present Foundation would be a good TV mini-series (and yes there are such things).
David Lynch already destroyed Dune. It looks like I, Robot will be trashed as well (plot-wise). If they screw up Foundation I don't know what I'll do. What's next: Jerrry Bruckheimer producing The Martian Chronicles?