TF2 dump ahead --
Force-a-Nature - At close range, hitting your enemy with every projectile, does as much damage as the Scattergun. The Scattergun shoots more rounds, uses less pellets and you don't need to find it first.
Bonesaw as the Amputator is better in every aspect, in the fact it has the same stats, but the Amputator has the taunt-heal ability and the Medieval Medic bonus.
Loch 'n' Load - smaller clip size, more damage to yourself, 'nades don't explode unless they get a direct hit. All for a small +20% damage.
Fan O War - weakest weapon in the game, period, it's max damage done is 13. Mark an enemy to take mini-crits for a few seconds is harder to do than to shoot them with your Scattergun/FaN/Shortstop
Homewrecker - other than removing Sappers, its main pro (doing more damage to buildings) is outmatched by the Flamethrower, which can destroy a Sentry, the Engineer, and the Dispencer all in one swoop.
Darwin's Danger Shield -- better max health... for a class that's close to always killed by one-hit kills (unless you're using the Croc-O-Style pack, admittedly)
Boston Basher/Three-Rune Blade - cause a bleed on yourself after a miss? Yeah. Totally a good weapon...