Nothing But the Calvary is Here
Whether she is most players’ favorite character or not, Tracer is the undisputed face of Overwatch. She was heavily featured in all the pre-release short films; her face is the one on the box and in nearly every event she gets a new legendary skin. Despite her obvious popularity, Overwatch has never had a mode solely devoted to Tracer. It is time. 1v1 duels with two Tracers can get insane as both players are desperately trying to rewind time to recover their health. Just imagine how exponentially more crazy things would get with nothing but Tracers running around.
This could be a standard Arcade mode where two teams would go up against each other. The catch is that it would be nothing but Tracers zooming all over the map, back in time and shooting each up. There could even be some lore for it like it’s what happened to Tracer when she was sucked through the time portal or if it is different Tracers from different universes battling it out for supremacy. Whatever justification you need it would just be a lot of rapid and ridiculous Overwatch gameplay.