Many have their opinion when it comes to the worse weapon in the game. Some will argue Classic, others will argue Manmelter, and so on. While those are fairly bad, none of those come close to worst weapon of all-stock melee weapons.
In a game where 5 out of 9 classes have a shotgun (and one has a Minigun), stock melee weapons can come across as bit redundant in close-range combat. This isn’t even mentioning how awful hit detection for melee weapons but if you’re interested in that this article pretty much covers that aspect. Although some will bring up Spy and Engineer as a counterpoint, Engineer’s melee has utility (constructing, healing, and upgrading buildings) and so does Spy’s knife to some degree (although I don’t think “killing enemies better” really counts as a utility).
So how do you fix stock melee weapons of the non-spy and engineer variety? Easy, by giving them utility just like those weapons. Just look at the melee weapons most non-spies and non-engineers use (barring the Sniper). Nobody uses the Disciplinary Action/Ubersaw/Boston Basher/Fists of Steel/Powerjack/Pain Train for kills. They’re used for their effects, whether that be mobility, health, damage resistance, and so on.
One possible utility to give stock melee weapons is stun, similar to that of the Sandman. This stun would have one difference from the stun we all know and hate-inflicting 30 damage or more on a stunned player knocks them out of stun instantly (credit goes to Jigglypuff of SPUF for suggesting the idea in a thread), meaning if you do stun a player, you better make that shot count or run away. Stun lengths will vary among classes, with Scout’s bat having the shortest duration (due to Scout being incredibly fast), and Heavy’s fists having the longest (due to Heavy being incredibly slow).
While many people will shun movement-impairing effects in mobility based games like TF2, bear in mind that you have to be at point blank range to even apply this effect. That’s not an easy feat considering all classes either have some way to knock you back (Soldier, Demoman, and Pyro), are hard to catch (Scout, and probably Soldier and Demoman due to explosive jumping), have long-range weaponry (Sniper), can go invisible (Spy), have a death machine by their side (Engineer), or are death machines (Heavy). Medic would be the only vulnerable target, and even then, a competent medic is usually never alone.
This change allows stock melee weapons to be more of a escape tool/one free shot, rather than a weapon you only use in silly game modes. Besides, consider the possibilities of this revamp with Buffalo Steak Sandvich.