While it isn't pretty now, it's a bit early to say this is who he's going to be going forward. I'm also not so sure it's due to the spotlight in NY. Elite closers struggle, get demoted and work their way back up on a fairly regular basis. I don't think Hader got demoted but he struggled for stretches when he could have been. He turn it around and looks Harder like. Taylor Rogers was horrible here and has and ERA+ over 100 ever since. Including 161 last season and is at 223 so far this season. Sometimes they become dominant again sometimes they don't get back to elite but are still effective. Even if he never returns to the best of the best it doesn't mean he won't be an effective high level reliever ever again.