I love Zenyatta. People say he's a shit primary healer but I disagree. Playing Mercy is sometimes as much fun as watching my car fill with gas. She only gets to do one thing at a time. Provide 60 hps sec OR add 30% damage to one person OR shoot her little pistol OR hide and hope the enemy team doesn't know where you are so you can surprise Rez.
Zenyatta provides half the healing of Mercy regularly and can provide it at a greater distance with a longer out of LOS effect and doesn't have to put himself in as much danger to provide it (although he lacks her escape tool to compensate. BUT then he at the same time also gets to debuff someone by 30% which if one teammate is shoot that target with at least 100dps worth of damage, you have now effectively provided 60 hit points of swing damage just like single target Mercy heal. If the teammate deals more than 100 dps, you've now provided more than Mercy. AND then you get to deal up to 300 dps (with head shots) worth of damage yourself. Not even accounting for his ult which I enjoy better than Mercy because for one it makes him invincible and second it prevents the deaths instead of hiding to let it happen.
I'm tired of hearing people say Zenyatta isn't a good healer. He does just fine. His greatest strength is how much he gets to do at the same time while Mercy has to pick and choose which thing to do. He can heal from further away than Lucio or Mercy and his heals are more reliable than Ana. He can deal dps-level damage and provide a powerful tool to help his team melt targets. And he gets to do this all at once.
Oh and another thing. He can be better at healing stealth mode as well. Mercy has to be in the mix with an obvious beam tether. Lucio has to be relatively close. Zen can throw discord and harmony from really far away and hide for 3 seconds (building up a volley of balls to shoot if he wants).
Not sure why I wanted to write a Zen love letter today. I just wish people would quit thinking Lucio and Mercy are the only primary healers. A good Zen heals just fine unless your team is simply outmatched. And he's a ton of fun to play now. Blizzard better not touch him. I think he's perfect post changes.