Okay just to clarify, no sword in the Napoleonic wars ever weighed anywhere close to 20-40 or even 15 pounds. Cavalry sabers were, on average, 2-3 pounds and 3 pounds is pushing it. While I think the officers saber is fine because its paper thin and balanced, I understand with the cavalry sabers because they are unbalanced, with most of the weight at the end. But if swords were slowed down it would only be fair (and realistic) to make them more powerful, after all, these sabers split helmets, severed limbs, and "clove heads asunder to the chin."
And I understand that briquets were not used often but its still a thick, heavy blade that could easily kill a man with a thrust or a slash to the face. If you look at how much a saber briquet weighs in real life, its roughly 2.5 pounds which is equal to the weight of a French cavalry saber. That kind of weight would split a face open to the brain. The reason these things weren't used in combat is because the bayonet was just more handy because you kept your musket with you instead of leaving it behind or carrying it on a shoulder strap. The briquets weren't useless, soldiers just liked to have their guns with them. Also sword bayonets were used and they were meant to be deadly slash-and-stabbers, there's no excuse for these to be so wimpy. They're bayonets too, just detached. The point that is indisputable is that a thrust only requires 2-4 inches to be lethal. So if I shove 12 inches of steel all the way into someone's chest, are the odds in their favor? No. The reason M&B's combat is so successful is because it's realistic and therefore skill-based and therefore competitive. Nobody likes trashing an opponent then dying with 1 hit because "lol sword bayo sux"