Hi Kara, You hit the nail on the head with your criticism of the Weekly Review. It's the single part of GTD folks have the hardest time with.
The fact is, there is no planning step in the Weekly Review. And that should be the entire point. Instead, it should be the Weekly Planning Session, intended to cue up the next week's commitments. That's more important than reviewing the past, as you said.
David Allen also prohibits time blocking in his books, (but he's changed his mind in other forums), so it's no accident that he does not advocate planning the future in any detail. He's just not a planner in his books (although I imagine he is in real life.)
I will check out the leads you suggest to set up a periodic planning meeting. Thanks for this point of view. For many people, it's a shocker!