“The original idea was to keep her support, and then you’d be able to do this full clone ability that she has now,” he explained. “But then, pretty quickly, we realized that ultimate is really cool, but it’s not really going to work as a support, because I don’t think you really want your healer to suddenly become a tank or DPS, and now you don’t have a healer. Whereas somebody in the DPS role is much more flexible. Now you have a tank, now you have a healer. So it feels like, if we’re going to do that kind of thing with swapping roles, you probably should start in the damage category. So that’s when we started going down to the damage route and developed the rest of her kit to support that.”
https://www.gamespot.com/articles/overwatchs-echo-plays-like-a-hero-designed-to-fit-/1100-6474958/