They traded Teel, Montgomery, Meidroth and Ehrhard. They completely whiffed on a few high draft picks (Zanetello, Anderson).
I think they've really improved the pitching infrastructure. I think the hitting side has stayed the same. The only difference is that they get hitters to succeed at AA, but can't figure out how to bridge that gap to MLB. It could be luck. It could be their focus on hard hit rate which pumps up numbers at lower levels and then reaches a high water mark at some point. Maybe something else?