Mei and Reaper will be shown some buff love in a future Overwatch patch.
Overwatch developer Geoff Goodman stated in a forum Q&A this week the team is "looking at" buffing Mei and Reaper.
According to Goodman, changes to the heroes will be available through a Public Test Realm patch, "hopefully this week," (thanks, reddit).
A question regarding whether a balance pass would occur before Brigitte was considered "sufficiently balanced and integrated into the meta," was posed to Goodman on the official forums.
"We’re always trying to get ahead of the meta and trying to predict what shifts are likely to take place," Goodman responded. "In this case, we’re seeing some potential for a big tank meta on the horizon, especially with Moira just recently being released and how good she is at healing multiple tanks.
"I’d certainly be worried about buffing heroes like Roadhog, Zarya, and even Ana until we can get a better gauge on how the game is shifting."
Speaking of Ana, Goodman also said on the forum there were a "number of things" the team could do for the hero. There aren't any firm plans just yet, as the character isn't "super far off," the meta.
"She does bring a number of tools that no other healer has access to [and] currently, she is more a victim of the dive meta than anything else," said Goodman.
You can read over the entire Overwatch Q&A with Goodman, starting with his answers, through the link.
The support/tank hybrid was announced as the 27th playable hero for Overwatch in late February.