Very good point. I think that, as a site where most of us are lightweight backpackers, we sometimes forget that not everyone is like us. A heavier pack does make it harder to walk on tricky footing. Along a similar line, how is your pack loaded? It works best when it is balanced from side to side, front to back, and top to bottom - with a low center of gravity, close to your back. An unbalanced load will work against you, and tend to pull you off-balance.