I haven't seen 1v1 Winstons yet. Zarya does require consistent aim and ammo managemnt, even if the fights are low energy. Torb is legit fun, for me anyway. Bastion is just trading damage and heal till ult, which then there's just a really short tank fight.
Though of all the 1v1s people call silly, Symmetra seems the most wrong. Sentry awareness, right click prediction, ammo management, and best of all, dealing with situations where you're both left clicking. There's far more depth in this than any 1v1 really. It changes the game from "reflexes and git gudder aim" to awareness and strategy.