I think map geometry is a large culprit in the prevalence of mobility.
On heroes like D.va, I don’t feel like mobility is inherently overpowered, but rather a necessary tool for her to function as a hero. She would be completely dead without it. Same for Mercy.
Overall, I don’t feel mobility is too strong. The problem occurs when mobility dps heroes become extremely versatile, and essentially allows for full on mobility comps where everyone can keep up with fast moving tanks. Tracer comes to mind.
First post, and the attempted Mercy hijacking has already begun. You’re faster than usual, aren’t you?