Weapons that are just worse than their stock counterparts. Not strictly worse like the Big Earner, where the upsides aren’t worth the cost to equip, but literally worse, as in there aren’t any upsides to begin with.
Once in a blue moon somebody on SPUF asks for these, and it’s always seen as a bit odd. There are two main flavors to the argument for adding these; the first is that they’d serve as a sort of handicap in situations where a player wants to limit themselves, either for training purposes or when playing with friends who are of a considerably lower skill floor than yourself. I can kinda see where this argument is coming from, but surely it can’t be hard to crutch yourself with what TF2 already provides. I’ve found the Degreaser/Manmelter/Sharpened Volcano Fragment/Jingle Belt is a pretty good loadout if you still want to have some fun and help teammates but not be capable of anything spectacular. Or, you know, you can just go Medic and play a completely subservient (but vitally important) role for your team.
The second flavor is the request for equippables that somehow prevent the user from dealing random crits. This is seen as some sort of “honor” code, from those proponents who repeatedly let random crits ruin their ability to have fun. The requests come in the form of a special weapon quality, a cosmetic, or even an option in the user settings. Arguments against this come mainly from the point of view of other players (newer users may get confused if they shoot a glowing critical rocket and the enemy scout doesn’t die somehow) but I’ve never seen this as possibly problematic enough to actually affect anything; after all, who hasn’t shot something at someone in Team Fortress 2 and wondered why the hell it didn’t kill them? My only problem with the notion is when the requests go a step further and try to wrangle a subtle upside in there by phrasing it “user cannot deal or receive random crits“. This would be a straight buff to a number of sniper and spy loadouts that already don’t deal random crits (Ambassador/Enforcer and jarwhacka being two extremely popular ones). Plus, it’s heavily biased towards treating random crits as a bad thing, and I don’t think Valve holds that opinion.
But I do think that “straight downgrade” items can be successfully implemented into TF2, and indeed a few exist already. The aforementioned Jingle Belt and its comrade the Bootie Time both Jingle all the way for no upside, and the Sharp Dresser is a stock reskin of the knife that doesn’t come with a taunt kill. Both of these effects are subtle and aren’t hurting anything. At the absolute minimum, I think it might be nice to add at least one option for every class. The jingling footsteps were given to scout and Pyro, I suspect, because they are the ambushing classes and loud footsteps get in the way of doing that. Perhaps the others could subtly affect the class roles of their wearers as well? A whistle for the Soldier and Demoman that trills loudly when they explosive jump, or a festive PDA for the Engineer that erects buildings with glowing colored lights draped on them. Cosmetics make a player more likely to die at a fundamental level because they help the player stand out and in most cases work directly against then concept of camouflage, especially unusuals. Most taunts that don’t have a combat-practical application are essentially tempting the player to risk death by using them, and over a dozen were added in the most recent major content patch.
So to sum this up, if I could add any straight downgrade into TF2, what would it be? Well, despite having just established that I feel the concept would only work as a cosmetic, I’d want to add a engineer PDA called the “GBA Tool”, it would replace the number screen on your build tool with a game of Brick Attack where you moved your paddle left and right with m1 and m2. Engineer can get really boring when on defense, and sometimes I’d love to screw situational awareness and just have something fun to do while waiting for some hapless foe to try and take the intel.