I’m an Ana main since she came into the game, I actually agree with you for the most part. Healing is a significant crux of gameplay for 3 players on a team, the supports and tank, and it has never felt right to me that a character has the ability to 100% negate all healing consistently.
The suggestion I’d make to Team 4 would be to reduce the Bio-nades effect to 50% and increase the duration to 4 seconds.