Overwatch's development team has heard the pleas for a map editor and is open to granting them, the game's director said, but it's not a simple or fast process.
Jeff Kaplan, posting in the game's official forums, noted that Overwatch was made with an entirely new engine. That makes releasing a map editor a long-term goal rather than a more immediate add-on. "We are extremely open-minded about releasing a map editor for Overwatch someday," he said.
"We have this on our long-term road map and believe heavily in user-made content," he said. "But there are many challenges ahead of us and it will be a very long road before our editor can be made available to the public."
Overwatch's newest hero, Orisa — a robot serving in a tank role — goes live today on all platforms after a couple of weeks in the public test realm. She's the third hero to join the game after its launch back in May 2016. She offers barrier protection to teammates, supercharge buffs for them, and a means of slowing down the opposition.