What ?
There are plenty of tall defenders who had good third years. Rance, Davis, Stratton, Andrews, Talia, who won the RS in his third year, to name a few. Even our own Oscar McDonald had a good and better third year than Weitering. I'd mention Lever, but you'd just say he played the easy intercept role. And I'm sure there are plenty of others.
Btw, being a young key defender is much easier than being a young key forward. Do I start listing all the key forwards who had good third years ?
So now you are cherry picking just one year?
Compare the 1st 3 years of any KPD's output in the last 10 years. JW's numbers are top 3