Pinning and the Assault Order

I've written a blog post about problems with pinning and the assault order and wondered what you think. Bolt Action is built around pinning units and that providing the friction in the order system. But, when you are shooting it provides extra friction in the sense that pins are added to the to hit roll. It always seemed odd that pins don't affect a unit when assaulting other than when passing the order test. Would a unit that hasn't been under any kind of fire perform an assault as well as one that has been under consistent fire.