Pretty much agreed on all fronts.

A lot of classic "Big Idea" sci-fi was like this, terrible as a book and as a work of fiction. Awful pacing, wooden characters, mouthpiece characters spouting exposition dialogue that no real person would ever say outside of an academic lecture.

Their value lay in the provocative ideas they explored and how the tried to look at the impact of social and technological change on humanity.

Of course, now we know that psychohistory is complete BS, history is not deterministic: Uncertainty and chaos reign.

But nonetheless, Foundation remains important because it is such a formative SF work, and had such a vast influence on the next century of SF that followed it.