If you're talking about ruckmen, it's often reflected in centre clearances. Last year, Richmond were getting smashed in clearances, because we didn't have a capable or true ruck man. This meant that as good a midfield as we were starting to build, it didn't count for much at the bounce cause opposition midfielders were getting the ball. Now we have Maric, our midfield can win clearances because he is capable of directing the ball down to Cotchin/Foley/Tuck/Martin.
Jacobs for Adelaide has become a capable ruckman too, and he can partially be attributed to Adelaide's success this season. Ryder was good early for Essendon as well.
I think Maric has become an elite ruckman due to his other super contributions around the field (contested marks/tackles/general smarts/endurance). Still a shade away from Cox and Kreuzer (and Natanui) who are complete players in so many ways.