Probably because they nerfed his range. Believe it or not, bap wasn’t a must pick when he was initially released. It was only after his subsequent buff to his damage and healing that he became one. His healing became less effective and more niche in OW2, we no longer have two tanks, and his damage got nerfed. It’s no wonder he isn’t a must pick anymore.
Ana, I feel like is wildly over-tuned right now compared to other supports. But I don’t think she’s OP, she’s just a lot more versatile compared to them, similarly to lucio. But lucio took a big hit recently with his nerfs, only ana is left mostly unchanged now.
I was very happy to see zen getting his buff though and I’m excited to start playing him more. He’s going to be a very good hero to pick to carry games in solo queue even more now. I just hope sombra isn’t going to get in his way too much. Also, I wouldn’t be surprised if his knock back effect gets toned down a notch eventually.
Last but not least, I just hope they don’t make brig too good at protecting the backlines. Because that’s one of many reasons why supports were kept were they were. Because of this assumption that brig was going to protect the ana/zen, it was considered “okay” to keep them vulnerable. But the only people who play brig are those in higher rank, so even if brig + ana/zen/bap was brokenly OP, it didn’t apply to the 90% of the playerbase.