I hope he does. He desperately needed a change of scenery.
I don't think he will magically get way better. I don't believe Pittsburgh used magic on Rivero either. Rivero has always had great stuff and the only big change I see is that he has traded horizontal movement on his fastball for more sink, and has slowly ramped his velocity up. He is benefitting from an insane sub .200 BABIP, just as Albers is with the Nats, but even adjusting for that, he'd have a sub 2.50 ERA.
Treinen isn't going to magically find control as a 29 year old. He is not Zach Britton. He is a guy who has control problems and a high velocity sinker that doesn't miss enough bats. He has had some bad luck, but he also doesn't tend to help himself more than enough.