My studies on this seem to be as follows:
As most people know, weapon speed is determined by a base value times weapon multiplier. You can move at a percentage speed based upon how strong you are and how heavy the weapon is.
What most people don't know: You begin hitting weapon strength cap very easily with base dwarves. Only the buffest dwarves can swing even mace-sized weapons at full speed. The additional gains you get for damage are such that it is generally very inefficient to use heavy weapons nowadays. Because damage is based upon energy, this means that lighter blunt weapon materials are almost always better, unless you have strength to spare. Relative material hardness seems to play a factor in the ability for blunt weapons to penetrate armor, but not in their damage output. While edged weapons seem to have their bonus damage based upon a multiple of surface area and penetration, blunt weapons seem to gain damage almost strictly from their ability to penetrate armor and flesh. This means that a high contact area bladed weapon is useful and might easily chop off limbs, but a high-contact area blunt weapon is just a recipie for reduced damage. This is not strictly true, but is a solid rule of thumb.
Edged weapons seem to have a bonus damage step before armor. Blunt weapons seem to have a bonus damage step after armor - a multiple of that base damage which went through. Both will penetrate armor at close to exactly the same point given similar contact areas and velocity. Penetration seems to be the source of derived edge weapon bonus damage, but I can't quite get a grasp on its behavior. An edged weapon with penetration 1 is significantly better in most ways than an equivalent blunt weapon. All blunt weapons in game have a higher velocity multiplier than edged-weapon counterparts to deal with this fact.
Blunt weapon penetration does not seem to have a significant effect. Equivalent blunt weapons with values of 1 and 5000 seem to function very similarly.
Knowing this I can approximate most behaviors, but I still only have a small image of the greater picture.
Ironicly, by my estimates, whips represent the best blunt weapons in the game by a pretty wide margin. I don't have too much experience with testing with them, but does that seem consistent with others? They would probably be better mechanically be represented by edged weapons with a large contact surface and nearly no penetration.
That is all my studies have reached for now. Does anyone have a further body of evidence on the subject to agree or disagree with my initial tests?