a lot of weapons in tf2 are not predicted when they pretty easily could be
off the top of my head:
force-a-nature jumps (#ifndef CLIENT_DLL in CTFScatterGun::FireBullet just needs to be removed)
demoknight shield charge (starting a charge is unpredicted, ending a charge by emptying the meter or by colliding is unpredicted, ending a charge by attacking is predicted)
sticky launcher charging (hud meter + sound are unpredicted)
huntsman charging (sound is predicted, speed change is predicted, but the hud meter is delayed and you can jump clientside during this delay which causes a prediction error)
loose cannon charging (completely unpredicted other than for the particle sparks effect, makes this weapon pretty unusable with high ping)
rocket launcher reloading (hold down m1 to shoot rockets as soon as theyre reloaded and you'll notice it wont make a firing sound, this doesn't happen with other weapons, you can also see that the rocket count updates slower at higher ping)
cow mangler alt-fire (speed change is unpredicted, hud meter doesnt update immediately when alt-fire is finished which desyncs the reload)
thermal thruster (completely unpredicted, even the holster is unpredicted, hold down m1 when switching from thermal thruster to the dragon's fury and the df will fire an unpredicted shot)
a lot of weapons in tf2 are not predicted when they pretty easily could be
off the top of my head:
#ifndef CLIENT_DLL
inCTFScatterGun::FireBullet
just needs to be removed)