I haven't played in a few months. Was Zenyatta nerfed recently? Especially on defense, he's been an incredibly effective dps choice when I played regularly
This list is more focused on competitive play and current meta, in which zenyatta is heals first, dps second. Same with the likes of ana.
But for supports, Zenyatta is still up there with Ana for best offensive output. Just know that's a secondary concern.
In quick play, whatever. Go attack mercy for all I care, as long as you communicate that and we have an actual healer.
As for him being nerfed, Discord was nerfed significantly, but that was more to do with team wide damage than personal damage. His orbs now do more damage actually, making him just slightly less of a threat against discorded enemies and more of a threat against multiple enemies in a cluster. His right click also got buffed, I believe...
For a long time, I played Roadhog when I wasn't a healer but I started playing Phara a lot more in the last few weeks and since then, my aim with Roadhog's hook gone to shit. My avarage used to be 54.7% in competitive (not a good percentage I know), now I barely reach 30% in quick play. Did Phara broke me?
I find the best way to keep your aim with each character is not to focus too much on them, but don't let them fall on the wayside completely. If you only play pharah for example, you'll get really good at playing around her splash damage and travel time that it will unconsciously affect how you use other abilities, like hook or junkrat's bombs or s:76's missiles. It's all about finding the groove you need to be in for each character and being able to switch to it easily.
I liken it a lot to playing multiple characters in a fighting game. If you play one character a lot, your hands will start moving on their own to do combos, even when you're not playing that character. If you're playing multiple characters, you really have to work hard at being able to snap into a different headspace, where muscle memory adjusts to your character and doesn't just take over.