He has made measurable progress on offense, you are right. Unfortunately, he's regressed in the field, and they've mostly cancelled each other out. The good news is that Rosarios defensive shortcomings are almost entirely mental, so hopefully they can be fixed. I've thought that Rosario would ultimately end up as a good 4th outfielder, but if he can keep trending this way on offense, and clean up the defense a bit, he could be an average to slightly above average corner outfielder for a few years.