Weapons come down to three issues: Size, Weight, and Contact Area. A large copper dagger tends to be very lethal due to its very small contact area, 5. That's measured in cm2 btw. For comparison, a dwarf-made spear has a contact area of 20, meaning that the dagger gets its damage 4x more concentrated for stabbing power. The second issue is size, a dagger has a size of 200, and a spear has a size of 400. That means 200/5 = 40 size per contact, while a spear has 20 size per contact. The dagger is approx. twice as good at penetrating than a same-material spear.
When it comes to blunt weapons, mass is a big issues. Warhammers and Whips, warhammer is size 400, contact 10. Whip is size 100, contact 1. That's right, 1. Warhammer gets 40 size-per-contact, whip gets an incredible 100-per-contact. Silver has a density of 10940. Given the wiki's forumala that weight = density * (size / 1,000,000) then the weight of a silver warhammer is 4.376Γ and a silver whip is 1.094Γ in weight. Taking their size-contact ratio into account, a warhammer will exert roughly 0.4376 kg/cm2 pressure, and a whip exerts roughly 1.094kg/cm2 pressure, which is exactly 2.5x more directed pressure.
But there's an added twist. The Velocity Multiplier is somewhat poorly understood, but is presumably a direct multiplier of force. A warhammer has a 2.0 multiplier, copying the way the hammer's mass is concentrated at the tip and allows heavier swings, the weapon's power gets a 2x multiplier. The whip, on the other hand, gets a massive 5.0 multiplier. This means those previous numbers come up to an effective 0.8752 kg/cm2 and 5.47 kg/cm2. That's a difference of 6.25x more power for the whip than the warhammer.
This is all assuming silver weapons. A silver war hammer compared to a steel whip (heaviest and lightest weapon metals, respectively) still comes out to .8752 for the hammer and 3.925 for the whip, a ~4.48x difference in effective power. This is why those goblin whip lords will chip bone on every single strike through 4 layers of armor and 3 layers of clothes. They're basically throwing around live ammunition. It doesn't take long for a dwarf to give in to pain, and then when he's on the ground, every shot is a headshot. That ☼Adamantine Helm☼ is garbage against a -Silver Whip-. The dodging and shield skills are the only thing that will save you.
Also, this is all assuming I'm not talking out of my ass. I could be completely wrong, but reading the numbers off the raws/wiki, it's obvious to me that whips are grossly overpowered due to their contact area and velocity multiplier. You may perform modding attempt and/or ‼Science‼ according.
EDIT: I just realized that I wrote a much shorter response on the Terraria forums a while back. Someone was suggesting a crossbow as a fast-firing, low-damage type of bow. I wrote out a response describing the crossbow's use in history and firing style, and that it was most commonly preferred because it hit very hard and could pierce a knight's armor. The only response I got was "lol, I wouldn't have written a response that long." Sometimes I take B12's community for granted...