I have followed the game myself, watched the vids (though it's been awhile), and read the BB forums here and there. I don't agree with this view as it relates to the tackles.
No weight? You really lost me there. We must be watching different videos. The only time you see major movement is when the player is airborne, and then you see movement as expected. As for the rest, you see actual momentum in play as the player falls down or continues their run.
The movement isn't all that much different from APF2K8, in fact, I think I saw several player positionings that looked very reminscent of APF2K8. There's an article somewhere that someone wrote up comapring AFP2K8 and backbreaker. I'll have to find it. The comparison will probably shock you.
When I think of no weight / momentum, then the first football game that comes to mind (next gen) is Madden.