I don't play Overwatch, but I do play Battleborn, the game everyone says directly competed with Overwatch and suffered for it. (Even though the games are only superficially similar.) If they did pick a Battleborn, the only one who I think could compare to Tracer would be Marquis, since he at least has an AoE time control effect, even though it pales in comparison to Tracer's time manipulation.

Though from the cinematic trailers it looks like there are some severe limitations to Tracer's time manipulation? There's at least a couple parts where Tracer can't rewind time when she needs to, or is tricked into wasting her rewind time ability only to fall into some other trap. Not sure exactly how that works.

Either way, if the opposing character is a Battleborn or a TF2 character, I fully expect Tracer to win. Not only is "rewind time" a difficult ability to compete with anyway, but even if she was somehow outclassed, the power of Blizzard marketing is strong with her.