Granted the Nats haven't really dealt a lot of "big talent" away in trades, but which players have actually blossomed to be better than who was traded for? Robbie Ray is the first to come to mind, but everyone else has been worse than what the Nats got in return.
I'm also really confused about how to value relievers. Felipe was given up last year and looks great for the Pirates, but has a weird .185 BABIP that he has never seen before. Sustainable? For a starter it would be a huge NO, but for a reliever, I have no idea.