Wow, a whole 1 year aye? That's massive.
Just face facts, Ryder started playing ruck this year after 2 years down back and he is showing more than Kruezer who started playing ruck last year, both are young, both a raw, except one thing Ryder has shown more, and that is fact.
Maybe if you take into account the ruck stats for Shaun Hampson as well, you might get a clearer picture. So far this season Carlton's ruckmen have won 423 hitouts compared to Essendon's 302 & Brisbane's 369. That is a significant difference, something that is not reflected when you look at both Ryder & Clark doing the majority of ruckwork at their respective clubs.
To do a truly accurate comparison on the basis of stats you would need to factor in the respective time on ground for each player, particularly since both Essendon & Brisbane have been playing with one ruckman each, with minor assistance from other players (in the recent Carlton/Brisbane game Brennan was credited with 1 hitout. Clark had 33 & Kreuzer & Hampson 40 between them).