Having played over 30 hours on Ana, I think a reasonable compromise is to keep the biotic grenade healing on Ana to 75/maybe 100. Biotic grenade damage to enemies and heal ability for allies should be nerfed. Ana is too strong, in the context that she is a ranged sniping healer. She is like Zenyatta, however, she has more survivability that Zen from the fact that she has Sleep Dart and the biotic grande. Zen getting flanked close range means almost certain death unless the Sender player itself is skilled enough to kill the flanker. That itself requires skill. Ana having sleep dart, which is an instant flanker denial is good enough. However, as I've noticed, even if I do miss the sleep dart, I have the biotic grenade to back me up. Even if a Solider hits me with Helix, or Genji dives me, or Reaper shots me 1 time, I get an extra chance to live simply because of the grenade. So Ana by virtue has better survivability compared to Zen, Lucio, Mercy. Yes the others can run away or fight to the death. Ana has 2 ways to live. This simply isn't fair and makes her a must pick especially if the enemy team has an Ana.