Both Tracer and Mercy were first romancable characters we added, and as it often happens with "first ones", they suck. Mostly because I'm, as a writer, been unexperienced in writing for VN games. If you compare them to any other route in the game, it is obvious that they need some kind of a rework, and that's exactly what we will do. Right now we're trying to focus on delivering an actual story, with conflict, stakes and emotions, and when we will get back to Tracer and Mercy, that's what you should expect.