At the current pace of 3 heroes a year. If they only released Support and Tank heroes to catch up to the current count of 16 DPS heroes. We’d have to wait 6.3 years for Support and Tanks to reach 16 heroes for each role. If they increased hero releases to 6 a year we’d have to wait 3.1 years and if it was increased to 9 a year it would be 2.1 years.
To increase the workflow and still maintain quality they’d need to hire a lot more devs. Given the rocky time the game has had, the abundance of Soon ™, and secret things they’re working on but can’t tell us. I don’t think people will wait around 6+ years for the hero roster to get balanced out with more tanks and supports. I want to believe the game will be around for another 10 years but who knows.