I’m talking about one reason why Zen isn’t as viable right now. When he and Mercy were meta, you had an exploitable support and a mobile support.
Since Ana is the top dog right now, and she’s another exploitable support, the two don’t pair as well since you probably don’t want a very low mobility backline.
Same with Bap. His immortality field could save Zen more often than not, but he also got nerfed and pushed out by Ana.