My problem with that is that pretty much whenever I shoot someone they're taking at least 20 damage, let alone over a 10s period, or if you combine fire from several mechs. The first LRM volley that hit you would mean you die -- look at how fast mechs already die when they're legged or knocked over from collision. I never thought the rule made much sense anyway. Knockdown from lasers? Knockdown from anti-armor rounds and missiles where all the energy goes into penetration?