They level the playing field when made truly random, not scaled off DPS when you're on a roll. Fuck it, you could even scale them off how an individual player underperforms, as opposed to how it is now. Completely deterministic combat makes even minute differences into all-out stomps, just look at Quake and its derivatives. This doesn't fit inside a casual, pub-first shooter.
Old Sandman is dumb, taking away movement and action from a player in a game that's reactive in nature sucks balls. Compare that to the mechanic some people complain about as well, airblast. You have the option to shoot the Pyro dead. If you're stunned, you are forced into third person and can't do shit but pray the Scout misses his cleaver. Complete cancer.
If old = good is your argument, a la Gabber, consider the literal pay-to-win cosmetic + weapon sets that used to be in the game. The most grievous offenders being Snipers you couldn't kill with a headshot (Crocodile), Spies with silent Dead Ringers (Fez) and Scouts that had more HP than you because they had a hat on (Milkman).